Most of us...  if we are honest...  have been scammed in some way.  It made me a big believer in TER and reviews.  
Newbies especially should stick to well reviewed providers.  The are too many scams to list all, the upsell is only one.
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Ok newbs, found this little diddy on the LA board. Remember nothing good happens late at night if you're only going to think with your little head.

well reviewed ladies.  With VIP (he could have had almost 2 years of VIP for what he lost) he could read the details in reviews and not been ripped off.

Got ripped off in Vegas.  Had a hookup set up with a well reviewed lady, but she stood me up.   I was hard up (pun intended) and called one of the hits I got online for vegas escort agnecy.  First girl showed up and after I paid her, she mentioned she didn't have any condoms.  Huh, isn't this your job?   I was pissed and asked for my money back.  The agency called me and I told them what happened.  They told me they would have another girl come out with in 20 minutes, which they did.  She was not nearly has good looking as the first and I paid her and as soon as I turned my back she ran out with my money.  Out $400 because I didn't do my research.  Well learned lesson.

I just posted a TOFTT message on another board and I'll repeat it here...we've all been in the situation, sitting in a hotel room and ready to go but the only returned calls come from shady or non-reviewed providers.  I enjoy the rush of trying to TOFTT, but never schedule for more than 30 minutes and never someone charging high rates...if I'm gonna get beat it won't be for more than $150!

Ive never had a really bad experience doing this...okay okay so sometimes it ends up being with someone not so attractive (B&S), non-GFE, CBJ...but I've had some great ones as well.