I guess for me it would depend on what "fairly rare" meant.
A card there's a hundred of ? I probably care, one there's 10 of? Probably not.
At some point the condition matters a bit less, unless there's a huge difference in price or quality. I'm not sure just where that line is for me.
And , the reason for that is.......
While I understand a seller wanting either a totally happy buyer or to simply refund. OR that a seller might think a buyer is just lobbying for a lower price It happens, some people make stuff up. I've had a couple that claimed some sort of defect and when offered a full refund including shipping both ways just dropped it.
For me there's a range that would make me happy. If it's for instance something that's usually $30 and I offered 25 only to find a ding or crease that went beyond what would be ok for the price, I'd still actually be happy at a bit under retail for the condition.
With the exception of things totally misrepresented, or things I'd taken a chance on. I've had more of the second than the first, cards that looked good but were actually trimmed, or ones with flaws I simply missed. I don't bother even asking on those. I took a chance that something was really good and I was wrong, that's not usually the sellers fault. (Plus I've been right a lot more often
)
Steve B