I am not sure about bet365 accounts, but regarding bitcointalk account many times already discussed on forum but admin has no respons about it. Moderators have no right to delete post if it's not against of forum rules or spam. Scam are not moderated by forum. So regarding account sale first need to change rules. Obviously account sales are not good practice especially on the forum.
Regarding bet365 there is rules for overall account sale thise need KYC.
Accounts on sites that require KYC such as bank accounts, PayPal, etc. are assumed to be hacked unless you explain why they're not hacked.
According to this rule mod could ask to prove that account has not hacked. If OP unable to proved then I think mod can take action.
true, i hope admin add this rule for this forum, i know what teymos said, but some people sell accounts with fake KYC