I remember when this probation was in the works and being made, I thought it was stupid and 15 years later I still think it is, The buyer has a right to change his/her own mind. Ever walk into your local grocery store, drop something in your cart then when you get to the check out you put it back instead of buying? Same thing. The store doesn't "black list" you. If the buyer doesn't want to buy it and gets cold feet, or if the seller gets cold feet at the last second, neither should be put on a list for it to "warn other members" The whole system set up here is absurd. CGC forum states that they aren't responsible in any transactions that take place, but they'll put you on a list? Give me a break.
The huge majority of the people on the probation list aren't on there because they "changed their mind". I managed a retail store for a number of years, and your comparison is completely off-base. The majority -- again, not EVERY single case, because no one situation is necessarily 100% similar -- are more akin to the people who tried to switch price tags on a item to get it for a lower price, or people who tried to return merchandise they stole to get store credit, or people who flat out tried to shoplift, or people whose behavior in dealing with a transaction was so out of line, that they caused a major disruption to the running of the store. THOSE people were essentially blacklisted, at least from the stores I managed.
Using a rare example as a means to ridicule a means to protect buyers and sellers from potentially dealing with persons who are going to end up being nothing but trouble is what's absurd. And "CGC" isn't putting you on a list, and if in 15 years you haven't figured out that, well no offense, that's kind of absurd as well.
If you want to deal with any number of the scammers, flakes, or bad seeds that have found their way onto both of those lists over the years, no one is stopping you. However, thank you for alerting me that, if I list a $400 book at some point down the road in a sales thread, you claim it, and then two weeks later after ignoring PM's finally come back with, "Nah, bro -- don't want it no more" and cost me a sale to someone else, that you'll see nothing at all wrong with what you did, then for one, I won't need "CGC" to put you on a list -- you'll be on my own personal "do not deal with" list.
The lists aren't perfect -- NOTHING in this world is perfect, for pete's sake -- but I'm continuously shaking my head at the people who ridicule what's largely been a deterrent to people pulling shady behavior, and a warning to members about people who may be problem customers. You don't like it -- fine, don't reference it and take your chances. But ridiculing it isn't productive -- you don't like it, come up with something better to help self-police the sales forums. If you can't, then all you're saying is nothing but noise.