That's the point of the TER rep. There is no guarantee, however it sounds like you are doing your due diligence to minimize the risk. Only other thing you can do to reduce risk is setup the date as an outcall, but from what I'm reading, you are as good to go as you can be.

you are 99.99% "safe."
Regarding who sees the form, could be a booker or her.  I suppose you are concerned because you provided personal info?
If comfy providing personal info to a well-established provider for screening, then I don't think the means of transmission of that info makes that much of a difference.

Sounds like you are doing everything right.  So now just relax and have fun!

...however, you can minimize your risk to acceptable levels.  In this case, it appears from what you have described, that you should be good to go. Both gals have multiple reviews by reviewers who themselves have written multiple reviews. The chance that either one are LE are very slim indeed, in fact, if the the reviews are good, the chances you'll have a bad time are also very slim. Relax and enjoy the journey.

To further reduce your risk, it might be safer to arrange an outcall instead of an incall. If they are Preferred 411 member then it's an additional safety measure. Since it's Vegas, there are quite a few providers who show their face clearly. I feel safer to book an appointment with them, especially if they have nude or semi nude pictures. As a last measure, you could contact other reviewers, who have more than 5 reviews and had seen the provider recently, to make sure the provider in question is legit. None of them are really necessary, IMHO, but it should make you feel safer. I don't feel any leo will spend that much effort to just nap 1 or few hobbyists. Once you book an appointment, you should just relax and enjoy the experience. I am sure the ladies will take good care of you.

p.s. You should probably spend more time worrying about keeping it a secret from everyone around you. The odd of getting caught by your SO, relatives, friends, associates, etc is much higher.

a review of the wonderful lady you spent time with.  

Enjoy!

and it's good that you realize that there are no guarantees in this enterprise.  But from your description of the providers with regard to the reviews, I'd say they are probably safe.  No, it is not likely that your email/website forms are going to someone other than her.  An exception might be if she has someone who handles all her bookings, many do use assistants to handle that.  Hopefully, she will do her screening of you as well.

Swim