Newbie Jail never kept spammers out, it just kept real newbies out of the conversations. People that are making accounts to spam have no problem waiting a few hours before being allowed to spam, they just create accounts in 6 hour shifts/waves. What newbie jail did was discourage the person with the intention of looking around at all of the boards and finding topics that actually interest or apply to them. If someone hears about Bitcoin and wants to come learn more, they should be able to without being penalized. If we penalize real newbies, they might just lose interest and leave.
The solution is people need to become more responsible with their money. Who gives their money to a stranger over the internet anyway? The only true measure of trust has nothing to do with the green numbers next to your name, it has solely to do with self interest. Over the internet you can't judge someone's character. All you can do is count on the fact that people wont scam you if they stand to make more by operating legitimately. Business owners for example (with some exceptions) if they are making 5 BTC per week operating legitimately, chances are they aren't going to scam me out of a few coins. Same thing with some long standing members here who run small businesses, services, escrow services, etc.
The status of someone's account, newbie, legendary, etc it doesn't make a huge amount of difference, besides the fact that accounts have some value here which plays into the self interest equation. Just stop sending Bitcoins to people without using escrow unless you can 100% safely rationalize trusting them with your money. If there is any doubt, escrow.