An issue with a tip button is needing the active key (to which the social portion of the application does not have access, and encouraging people to grant access frequently is not a good idea) in order to send funds. One solution which has been proposed is a separate 'tip wallet' which can be sent using the posting key, but some people object to that, saying it would make the posting key (and apps which use it) a lot riskier.

It is a tricky problem.