Sometimes there are people sending "*****bank",etc,
is not it a violation of the rules to have multiple accounts?

No. You are allowed to have more than 1 account, usually people also have their own bank account. FYI you aren't allowed to join in any contest in Bitsler with your other account
does anyone know why they do this?
i have always seen these "tips" from xyz to xyzBank and i have never been able to figure out what could possibly be the reason why anyone would do such a thing! what is the point anyways, just keep in one account or withdraw to your wallet if you want.