From what I have heard/read,the decision of an escort NOT to have sex with a client is not really an option.
All the these escort agencies are is legalised prostitution under a polite name.
When a client pays for an escort (male or female) it is basically up to the client whether or not sex happens,it's not up to the escort,and IF the escort refuses it could lead to an ugly situation.
Not something any amount of money would get me to do!
I would not advise it, agencies might say they are escort only, but I am sure there is more to it. I would think especially for a female, it could be a dangerous thing to do.
The money might seem enticing, but I am not sure how safe they are. If you do want to do it, make sure you are with a very reputable agency. Always let people know where you will be.
That can be a hard quest to get into. Escorting usually means sex for most of your clients. They do exist but these agencies are kind of hard to find. You can try looking it up in the Internet through google. They usually promote their site to their clients through Search Results.