It is already fishy when someone tries to approach me randomly with that kind of message. This become a common thing from the scammers that they'll enticed you with some amounts of money that you might not be able to decline.
And if someone asks me that way, no way. I'll just ignore it and won't even reply to them because the more that you engage to them.
They're not going to stop you bothering and they see you as a good prey that might fall for their trap. So, it's not with Telegram only but also in other messaging platforms.
You are absolutely right to be suspicious if someone you do not know offers you money out of nowhere. It is common trick used by scammers to tempt people. Best thing to do is ignore and not reply and report and block them because if you talk to them they will see you as easy target and keep bothering you. This is not just problem on Telegram but on all messaging apps so staying alert and cutting off contact right away is safest way to protect yourself.
Don't entertain people that you don't know and going to come by out of nowhere. They have sure a bad intention why they have approached you randomly with some offer of making money.
That's odd isn't it? and that's why this trick is starting to be known by many of us. But it's just sad that we always have newbies coming in and they're the targets at most times.
So, we have to continue letting others of how the trick goes with such messages.