if someone offers you cash, and you believe that offer to be genuine, then it’s theirs as far as I’m concerned.
This whole dibbs thing is toss, as I believe it puts off other buyers who may actually take the item as they think it’s already sold. equally the number of picture collectors on here that request pictures and you never hear from them again is ridiculous. There’s quite a few people whose “pics please” will just get ignored from me as they seem to want pictures of everything that’s for sale!
Equally if I get an email from someone that sneaks in before an email from someone who has also posted a reply here, the latter gets it every time.
But the one that really gets me is the WTD ads where you post up and say “I’ve got one”, and they post up “i’ll take it” and then expect you to then email them. I’m lazy, you want it, you make the effort, after all you’re trying to get it on the cheap more often than not!