I don't think it's an issue with the board police. It's more about making things crystal clear to potential buyers. What if someone throws up the and tries to pay with PayPal, then the buyer says "my bad, I don't take PayPal." If it wasn't clarified in the initial post, then it opens up a slippery slope and room for all sorts of confusion and ill-will.
I expect no more than what the boards currently require - method of payment, method of shipment, and returns. Don't post items for sale on multiple venues. Provide pics and a description. You wouldn't think that would be too much to ask, but apparently it is.