There's nothing to be careful for. If someone asks you to "invest" in their unregulated, made-up worthless token, and you do it because you convince yourself that it will go up in value, then you're getting what you deserve.
Greed is one of the seven deadly sins for a reason.
Some people just get themselves blinded by the love and trust they have for a particular person, which is why, without giving it a second thought, they can just go ahead and invest in something even when it appears to be too good to be true; they just go ahead to invest because they trust who advertises it, while sometimes some just know what they are doing and still think they can be too smart to be among the early birds who can make a profit before the crash but get themselves drained in it.