Screening using TER can include reading a client's reviews, and looking at his whitelists, perhaps contacting some providers that he has reviewed or who have whitelisted him. You can also PM the client through TER to make sure it is not someone else using his/her handle. Some providers even use a TER member's board posts as a form of screening.

On p411, you can look at a client's plays, and some providers will contact the providers who gave the okays.

Many providers do use verifyhim and other similar sites. There are lots of other screening methods. Some of them are best not shared on public boards. Perhaps some ladies will share with you by PM.  
Good luck.

I have people get frustrated with me because I do require references from an established provider.  I need to be able to see the providers TER and she needs reviews to count as a legitimate reference. I know someone that owns a local agency that will verify newbies and I usually refer them to him.  He always tells me I'm missing out but I just feel much safer when I get the greenlight from someone else who has actually met the potential date.