I recently heard that all foreigners registering their car here get that kind of plate numbers.
Yes. Of course this is what is referred to as technically illegal under EU law but since when did that ever bother Poland.
Personally I look forward to the day I get really bored with Polish red tape: I will then proceed to register a right-hand drive car and get it on non-foreigner plates and laugh manically when I am stopped from doing so.
As for driving a bankomat: just bribe the police in the usual Polish way.