“We reserve the right to deny any post and cancel any account at any time at our sole discretion.”

You can see where wanting to be paid and wanting to not sell out may be in conflict. Might want to put that on the list of “Things to Clarify” as well.

It looks like you’ve found an error on the definitions page. From the advertiser side, this is what you see when you click help for Tone:
“Positive means the post has to be positive, neutral means it can be positive or negative and negative means it must be negative.” Thus, advertiser expectations are set for open tone as I described.

PPP’s CEO, Ted Murphy has also blogged about it here: http://blog.payperpost.com/2006/10/attention-advertisers-keep-it-real.html

I will share the mismatch with customer support…

Tone – as determined by the advertiser, may be positive (speaking highly of something), neutral (more factual, not overly praising or harsh), or negative (critical, unfavorable, fault-finding).

This is in their opportunity definitions. So in that context, sure, you could be a little bit more positive, or a little bit more negative, but the advertiser still reserves the right to pay you…or not.