If my plan charges 1 cent per text received while roaming and I get 1000 spam texts, it hits my pocketbook, but it's not stealing from me?
Again, there is difference -- bot click is theft for direct benefit (of whoever runs bots). Mobile roaming example ends benefiting network without direct intention.
But this is all rhetoric that can be argued one way or the other. Bottom line is -- I don't believe (majority of) add clicks are bot generated, because higher scrutiny of publisher clearinghouse, i.e google adsense. Would be interesting to chat with someone from google about it