Juliet you are right. Any decent search engine (IMO) wouldnt allow incentive searches in the Terms (or on the sly if you know what I mean).
For one it's too risky. You allow people to send incentive searches and of course that is what the feeds consider (which I dont blame them) "trash traffic" and you asking to have your feeds deleted which means what $$ will you pay your members with?
I personally wont take that chance. Matter of fact I wont name any names here but I just signed up for a PTR site because I have noticed alot of traffic coming from there and LOW and BEHOLD if the webmaster isnt sending NOT only paid searches but targeting words too!
Most search engines will delete you for:
Incentive searches
Targeting keywords
Open Proxie traffic
Bots/cheat software
Content of the page you are sending traffic from NOT written in english
Just to name a few
Just to add to this. I just signed up for two more PTRs just to catch the webmaster sending paid searches.
Fair warning. I am not above signing up for a PTR only to catch someone sending paid searches