Yeah, I've heard that that is not such a good idea.
We all know google hates PTC...
But i was wondering, If I buy cheap traffic from ptc sites without having any google adsense on my website, do I still risk getting blacklisted on google or banned from adsense?
I do know some people who got banned for putting adsense on their GPT/PTC website
Why won't you do it?
If it's an affiliate blog and it isn't very good to SEO it as it's a well talked site (Hostgator affiliate site for example) than I prefer promoting in ptc sites and not getting listed well in Google (which I didn't before) than don't get traffic from Google, and don't getting traffic from PTC
Play safe is more better, my friend
Google have very smart system to tracking you're joining ptc or no. Not just PTC, but google is hate site which joining paid to program such paid to survey or paid to review.
PTC --> google hate it because there is a probability that PTC member is clicking your adsense site. And it's because PTC increase your page impression
PTR --> google hate it because it's same with buying a link
There is no risk of getting blacklisted, if there is no adsense in your site/blog, but google adsense of course will refuse it if you registering to adsense in the future.
Remember my advice, play safe by read and do what stated in google ToS