I'm not certain there's any real difference of opinion here, or at least there is little difference off outcome. I may be wrong.
One person has angst or maybe even a degree of resentment when new people or uncaring people don't see the rules or ignore the rules or get pushy and greedy.
One person doesn't mind saying "no".
Dave's rule is "don't ask unless it's offered", so that establishes what is "proper" for this community. No guilt-tripping!
(I always figured that if someone wanted to sneak around that rule, they would email or post lavish praise and interest, and maybe ask if the owner knows where THEY can go to order a plant like that. It would be pushing the limit to add "Boy, I would trade this or this or THIS to get a plant like THAT ... or pay up to $XX!" Then stop just short of asking for a trade or purchase. Why even break a rule that's so easy to bend? Even jerks, I would think, would understand that polite-and-wistful is more likely to be rewarded than pushy-and-obnoxious. That's why I would assume that most violators are ignorant rather than defiant)
Dave doesn't think it would be good for the site to have "enforcement" unless something gets abusive.
I know one site where many scammers have tried to get free seeds over the years, and the moderator tries to track them through IP addresses, and maintained a list of known aliases. That enforcement does leave a bad taste.
I think we all are at least somewhat irritated by really selfish, uncaring people who want something for nothing and get mean if denied.
Probably most of us wouldn't want to beat someone up for an honest, polite request if they never noticed the warning.
All that said, I see both sides. I lean towards discouraging greedy people from taking advantage of generous people ... but we're all really lucky! Dave made the decision, so we don't even need to think about it.