Sign 1: You find yourself asking, "is this a scam?" Just by asking that question, you're 99% of the way there. It's almost certainly a scam. Any icky feeling, any doubt, any bad vibes, or confusion, trust it.
What to do: The most important thing to do is just hang up the phone or ignore the email. If you have a bad feeling about something, hang up the phone, block the number, mark the email as "junk" and move on with your life. If they call back, block that number too. Repeat as needed. If you need that extra 1% certainty, Google it. Go to your search bar and type in: "[fill in the blank] scam." You'll likely find dozens of results confirming your suspicions. Even if you don't, there may be some similar scam with the names and details changed.
Sign 2: Urgency. Scammers will do everything they can to make it seem like they are calling you about an emergency. They prey on fear and panic because they have to. Scammers depend on this because they're asking us to do some stupid things, like give out our Social Security numbers or account numbers over the phone. When we are afraid, our thinking becomes foggy. We get tunnel vision and miss obvious clues. All these things work in the scammer's favor.
What to do: Slow it down. Pause. Put the phone down, and take a deep breath as you reflect. "Why would they be calling me instead of sending a letter? Is there really even a division at my bank that has that name? What would Nicholas say to do here?" As urgent as their demands may seem, think about your experiences with our actual government. The Post Office. The IRS. The DMV. Think about how long it takes to get a new passport. Do the words, "Please allow 6-8 weeks" sound familiar? They should! Whatever sentiments you may have about these organizations, I think we can all agree that they are NOT known for moving fast. Same goes for your bank.
I have another rule that applies to this situation pretty well. "If it's important, it's probably not urgent. If it's urgent, it's probably not important." There are exceptions to the rule, but it's mostly reliable. The biggest decisions often take years to make, such as who you marry, and whether you want kids. Meanwhile, debating whether you buy crunchy or creamy peanut butter at the store should take about 6 seconds, tops.
If the IRS really is pursuing action against you, they'll send a letter, in which they request a response by a certain date. Audits can take weeks or months. Legal proceedings can take years. Under no circumstances will they call you, demanding that you do something urgently, because THEY don't do anything urgently. If you still aren't sure, hang up on them and call your CPA or investment adviser.
Sign 3: Manufactured Legitimacy. If you stay on the phone with these people and ask reasonable questions, there are a few things they'll do to seem more legit, all of which are bogus. They might connect you with their "supervisor," who just happens to be available right at that moment (remember, urgency). They might provide badge numbers, titles, and specific names. These are all fake. They might direct you to fake websites, or have their scam-pals call you from separate numbers to impersonate relevant officials.
What to do: Go to the primary source. Don't use the website or email or phone number they provide you. Look it up yourself, using the same web address you normally use, or what you find on google. If they're saying your bank account has been hacked, hang up, and look up your balance. Likewise, look up the actual number for "Customs and Border Patrol," or your bank, or your city police department. Whoever the your caller is pretending to be. Ideally, go in person to the institution. It's much harder to impersonate your local bank branch in person than online.
Keep in mind that anyone can create a website with any address, as long as it isn't already taken. Usually, government agency websites are short. Think, cdc.gov, ftc.gov, irs.gov, sba.gov, cbp.gov You see the pattern? These 3-letter web addresses are very expensive to obtain. Scammers will go for something available like, "centerfordiseasescontrol".gov.
See what else I did there? "Diseases." It's not the 'Center for Diseases Control,' it's the 'Center for Disease (singular) Control.' But if you're panicking, you might miss that little clue.
Same goes for phone numbers and Caller ID. A lot of people don't realize this, but you can actually buy phone numbers, and set Caller ID up with whatever name you want. I can call you from a Washington, DC phone number, posing as President Biden if I want to. "Hey Susan, it's Joe. Listen, I need you to wire me some money. No time for questions. The fate of the free world depends on it." That would obviously be a fake.
But it's less obvious when you get a call from "Officer Lopez from Tijuana," claiming that your grandkids have been apprehended while partying south of the border, and "if you don't wire money right away, your grandkids will be put in federal prison with some really bad dudes." At my previous job, a client of ours actually got this call. It was scary for her, but she did the right thing. She called her son and told him what had just happened. Was there any chance his kids were in Tijuana? Her son wasn't sure, but within minutes was able to check in with his daughters. While he could not confirm whether or not they were in Tijuana, he could at least verify that they had not been arrested.
The lesson here is that if you're not sure, hang up on the scammer, and call up a trusted friend or family member and repeat to them what you were told. Ask them if it sounds real. A lot of people who get successfully scammed don't do this for fear of embarrassment, but trust me, you and your friend will soon be laughing and joking about other things. And your friend will be better off too, knowing what to look out for. You can also call your kids. You can even call me. I would rather spend 5 minutes putting your mind at ease than see anyone I know get scammed. I won't make fun of you, either. I'll just say, "yeah, scammers suck. Anyway, do have any fun weekend plans?" Everybody hates a scammer, and we are all on your team.