Drevv, tricky is asking question's for me so i just registered so i can be more direct I'm a moderator in a chat room and cannot ban people with spaces.
for instance "Dani ." when they log in the "." disapears and its just "Dani " and its impossible to ban the person who does it like that 15 characters or not, i just tried your theory. I counted 15 spaces including dani put the quotes and all it said was "Dani was banned" not "dani " so the spaces go away.
Also, someone with the nickname "." cannot be banned either quotes or no quotes. Don't know if its a glitch with PHP or I am doing something wrong