u should be careful when buying bitcointalk accounts as some have been banned several times. don't be surprised if u buy an account and get a 2month ban a few weeks later.
So how to identify the account was being banned before or not? Because when we deal the price with the seller they sure didnt want to give any description about being banned or not so its impossible to be careful too since we dont know anything about which id is he going to sell
You can't. Best you can do is use an escrow who will check the quality of posts thoroughly and if they're found to be poor or from a known banned account the deal will be terminated.
That means we need to ask the escrow for checking right? Or they can auto check it for us? Because some of people just only asking about the loaning, negative trust, post count and activity.They didnt even care other things and if there is already good then the deal is being made
If you don't request it then most wont bother as that's not part of the deal. Quickseller seems to check posts when he escrows but it would probably only be a problem if the seller had stated the posts were of great quality when this wasn't true. Accounts with one owner and great posts tend to go for more I think so people will start lying or exagerating to try boost their accounts up.