Yes I agree with this, I do think apps doing this would not be popular with users. Like a bitcoin wallet that took a wee bit of a users cash by altering the fee down a smite, or mining without consent (like the anti virus recently), I think users would be pretty annoyed.
This is where OSS apps are very good as it’s caught fast, but even non oss apps will be spotted doing this. The problem for the app is or will be (I think) to be successful it will need lots and lots of users like the anti virus chappie and the community won’t use the app in that way. The arg we can get a bot would also apply to AV folks and did not or a google competitor wanting to fill up all gmail with files (gmail fuse tool was never banned) etc. Or get a bot to click on your youtube videos to get advertising up etc. (not different as some server based snooping can catch this faster).
So my argument is scale of the attack required (as network grows) as well as ability to fool the public long enough.
Looks like public data will be costed at same price as private and structured data is X 10 (well each SD is a charged at a full chunk cost). Each chunk will more than likely (testing) be charged at same rate, so creating very small chunks will be a bad thing to do for any app.