It estimates since I installed it that I've cost advertisers $460 in clicks.
I wasn't convinced it was very useful and thought it would only take some easy heuristics to filter out when I first saw it, but if Google removed it from the store, it must have been a pain to deal with.
Maybe I'll even end up using it.
Generating click fraud on your favorite web comic's website or other small websites you may be visiting is pretty sad. Adsense bans for life.
(I'm not sure what the tipping anecdote is supposed to mean, but I don't understand why US customers put up with tipping either, the business is responsible for it's operating budget, and there is no legitimate reason to bother the customer with it.)