What forbids someone doing shit not answering to you truthfully? Or not answering at all or answering wrong because they would like for you to blame wrong people?

> I heard only nasty stories about Russian tourist

Edit: and this is doesn't answer my question: did you have been able to distinguish between them? Did the people who told you nasty stories could distinguish between them? In 2022 it is much easier because they haul their flag almost everywhere, but before that?