Can someone help me to understand how independents screen clients incase they are under cover cops. because an agency i know says they screen the clients but do they really? and how?

I have a form on my website that requests name, number (cell and work),two provider references - these can be circumvented if a member of a reputable screening service, oh, rank, serial number are great also!
I use everything at my disposal to make sure the guy is not only legit, but safe.

work number verification, other provider referrals, and phone number searches.

There are a myriad of ways to verify guys.  Some ladies use several and some ladies only use referrals from other well known providers.  

It is up to the ladies discretion how she screens, and yes most of the good ones do.

Personal Information: It is customary to request the following information: full name, cell phone number, email address, company name, & main company switchboard. The goal is for the provider to request to speak to the potential client, through a third party. This is a good way of screening, if you do not trust others to screen for you & you have extra time. The downside is that is it fairly easy to create a company, website & 800 numbers.

Provider Reference: It is customary to request the following information: name, email address, cell phone number, previous provider name, email address & website. I happen to request two providers. The goal is too make sure the potential client is well behaved, because he has seen a provider before you. However, in order for this to be successful, you should check out the providers you are contacting. They should be reputable, meaning that they have at least 3 favorable internet reviews, done by known hobbyists. The downside to this method is you have to rely on other ladies. You may not get an immediate response, due to their schedules & internet access.

Verification Services: There are three main verification services: Date-Check, Preferred411, & RoomService2000. Date-Checkrelies on reputable providers to bring in other ladies & clients to their website. Advertising is generally free to ladies & the gentlemen get a 60 day free trial. Date-Check only allows reputable providers on their directory. Preferred411is almost identical in concept to Date-Check, except they will allow anyone on their directory. RoomService2000 was originally started in Chicago & it most popular in the Midwest. It is fairly useless on the east coast. Unlike Date-Check, RoomService2000 requires ladies to pay for advertising & using their service. RoomService2000will accept anyone on their directory. My personal preference is Date-Check.