Just because a vendor pays a security deposit doesn't mean you have to drop your guard, of course not. But it does mean the waters won't be overcrowded with intentional scammers, since they wouldn't be up for paying a security deposit they would inevitably lose. They'd find another way, another place, just not here.
It may not be Amazon but it is still just a marketplace, though fractured by self interest, and any such marketplace left to self regulate against the worst excesses of human nature is doomed to fail, it's why we have reasonable rules against poor behavior in almost every area of life. But someone in a position to has to take the lead.
You won't lose your suspicious nature just because there aren't as many scammers as there were, the fewer will get smarter and require better observational and critical thinking powers than when they are so many and more or less obvious - it's the long termers would be the problem then, which means you'll have to get smarter too, more awake not less - and adapt any system of care to suit the situation. Think of it as a challenge rather than a loss of stimuli to your suspicious nature?
Good vendors are already discouraged, by the rep here for scammers - scammers ruin the place for everyone, by lowering the bar for standards of vendor behavior and discouraging potentially ethical vendors - as some endeavor to be, but even the best intentions need regulating where there's a lot of money at stake. Thing is though, you can't know how or if a system of deterrence, a security deposit, would work without a concerted effort to make it work.
I think your idea of a blind and random testing of established vendors is a good idea - have recently seen complaints on some established threads for exactly that, poor standards - while at the same time I've seen the vendor profess the highest standards. People need to be kept honest, as left to themselves, like any other 'self regulating' industry, they get lazy and/or careless, or worse. And they get away with it because nobody's holding them to account, effectively. So we could have a star/penalty system for vendors based on that kind of thing. But who's going to do it, it requires somebody to work at it.
You've got to start somewhere, and seems to me the best and simplest place to start is at the door with a system that discourages poor behavior in the first instance, at the door and not after they've been let in - though that could happen too, and deters intentional and would-be scammers at the same time.
I don't see it as 'incentivizing people to be less careful', people are going to be careless whatever is done. I see it as incentivizing vendors to perform as reasonably expected, to deliver the goods in an honest and timely manner without all the angst of suspicious and even hostile members - if you'd seen some of the receptions some recently introduced vendors received because of suspicions generated by the prevalence of scammers taking their hard earned cash - admin had to threaten to ban them, but it's not the members fault, it's the system that allows scammers in to easily.
To really see how it would work, or not, requires it to be tried and tested. Holding a deposit against bad behavior is a tried and tested form of guarantee of good behavior. And as with anything there will be hiccups, it's not an antidote to human nature or greed.
But in the absence of anything else the potential loss of money to intentional and would-be scammers requires regulation, or it's just a scammers fishing pool and everyone takes their chances. I think we can do better than that.
Would be great if it was the best but it is sure a start.
