Unofficial answer; the seller can choose whomever they like to deal with. Responding first doesn't mean a thing.
There's no commitment to meet until a day, time and place are agreed, through pm's, if you want to be able to neg a no show.
I hate those pages that take an age to load, keep jerking back to the top and then some nonsense vid starts blaring at you.
I'm thinking there must be a plugin to kill them ?
NEG = Mutually agreed time and place to meet, no show without reasonable or sufficient notice.
No one's committed to buy until they have an opportunity to inspect the item.