[jakeonthemove]

They seem to really hate any and all pre-sales, plus they have a list of "risk items" - if you're lucky not to fall into one of those categories, it's a happy life with Paypal for you :-).

Then there's their automated fraud prevention system that is just too trigger happy. As an example: I bought an item on eBay the other week and they refused to process the payment. A couple of days later I decided to try again before buying from another seller and it went through without issues.

[kevinconroy]

Based on what's said, it seems that businesses/groups that raise large sums of money sporadically trigger the most problems.

If you're running an on-going business that has multiple to many transactions everyday over long periods of time, then I suspect that you're less likely to trigger these problems. But again, YMMV.