This is why you need to be careful with sites like Sythe; a lot of people here are just here to steal from other people.
A few tips I've picked up over the years:
-Post count/title means *absolutely* nothing. Titles are very deceptive for new people, especially the higher up ones like Apprentice - it seems as if they're a member of staff or earned a rank when really it just relates to post count
-When looking for trustworthiness, look first at vouches and then join date. Ignore vouches from Moderators and OMMs, people just collect them because they look good. Ignore vouches where the user went first, these are useless. The same goes with vouches for GFX and account training services; utterly worthless.
Join date can indicate trustworthiness as long as you use common sense. I'd say a good 90% of scammers are banned within a year or two of their join date. A lot of them (especially those who sell membership) try to get a lot of honest vouches before leading up to a big scam. I cringe whenever I see someone who joined last month selling gold or whatever and everyone readily agreeing to go first just because they have several vouches and a flashy signature.
-Never trust someone who's too eager. This includes people who want to buy all your stock, people who pressure you into buying/selling NOW etc. In fact a few days ago I was talking to someone called Jive_Turkey and not only did he want to buy all my GP stock, he wanted to buy all the random items I had as well and mentioned he was trading with a few other people at the same time. Of course he would only agree to me going first. I cut contact with him and lo and behold, a few hours later he was banned for scamming three other people.
If it looks like someone is gearing up for a big scam, be very cautious. Before you trade someone, check if they've posted on a bunch of threads just like yours.
-Finally, use your instinct. If someone sounds young or uses Ebuddy (a sign they're using a proxy), has poor english, insists you go first, tries to compromise with a 50/50 trade despite having no vouches etc. just don't take the risk. Missing a trade is ALWAYS better than being robbed.