if we pretend someones reputation is instantly destroyed after the first scam, which it isn't cause it's a word against word scenario, you could also inverse the situation and falsely claim you've been scammed. that market would be dead pretty quickly.
so you probably can pull this multiple times befor no one trusts you anymore and then there is still different time zones and language barriers that restrict word of mouth which leads to more scam oportunities.
Ok...if you want to believe orb scamming is a thing then go ahead lol. I've heard of all kinds of scamming in FFXI. KC scam, oboro clones etc. Just not mars orb sales. If it's a thing then at least someone would said something in discord, or post on forums, or yell in public channel.
ofc there are more profitable scams but for the bumba clear one in your example you'd need at least 4 buddies or multiboxes or find a fool that pays befor you assembled the party.
Finding 4 buddies to split 200m is still WAY more profitable than making 3m alone. :P
it is a trust based trade and you need to be aware of it befor you engage in it.
There are way more trust based trade in FFXI everyday: selling CP/ML, selling gears, selling Odyssey clears....etc. All of these services cost far more than mars orbs and happens way more frequently.
And for whatever reason people are worried about getting a scammer from orb sales but not every other more expensive transactions? That's kinda weird lol. I'd worry about Mercs took my 50m then run than an orb seller took my 3m.
Also just FYI,even if orb scammers exist, they don't even need to pop the orb. They can just take your 3m outside of BC and force d/c. So any additional steps to stop them from disbanding party or D2 after they enter are not necessary.