I rarely sell anything here, so it's somewhat irrelevant, but in the past I added something to the effect of,
"If multiple people contact me about the same card, I will give preference to the guy I'm friendly with. Hope that isn't a problem."
If it's
friend versus flipper (Yes, he can do whatever he wants with a card once he buys it. It's not about that.), the friend always wins...even though we pretty much know nothing about our online
Net54 friends, do we??

