smiley/ symbol in app name


Just wondering: has anyone heard of rules about symbols in app names?
chess game ♘
…or just to highlight the app in lists ✰
I realize that this can create issues (not sure in fact, since there are thousands of japanese apps with such unicode chars in their names) but I’d like to know if anyone got banned for just one symbol appended to the app name or developer name.

note: I suppose that this goes in the “marketing” section of this forum

Thank you