The word busker in English literally comes from the word for basket in French. In Paris there's a tradition of placing a basket in front of you as you play/perform.
In fact, it's been my experience that even when you really aren't seeking any compensation in coinage, some people will place currency in your guitar box hole, stuff it in a pocket of your shirt, or literally try to stop you so that they can have the pleasure of placing it in your hand directly...SO, having a basket in front of you becomes a COURTESY for the folks that are using currency/coins as a way of saying YES! KEEP IT UP...Isn't thinking about the matter this way a lot more creative and positive about human kindness than ALWAYS thinking economic tranaction is ALL that motivates us to behave the way we do?
WICKER IS FUN
The more of your personality you can communicate with your "set-up" - the less of a stranger you are...I put my heart into my songs and writing, and often get responses that people are thankful for the presence of such feeling in their day...