As one who TOFTT with my first encounter, I have stuck with only the reviewed providers since being burned.   The ones that have a number of reviews, especially those from hobbyists that have done several reviews, just aren't going to turn up to be LE.   Problems of being ripped off are another issue, though, and I'd put the odds of that happening from CL or the back pages at about even.    Some thoughts about minimizing the risk of LE, though:
- One who is providing an outcall service is less likely to be LE than an incall.
- The longer you've seen the ad running, the more likely they're legit.
- Photos that look like models are more likely to be LE than your home made variety pics.
- Ones that put coochie shots in their ads are more likely legit.  Good chance of an upsell, but less chance of being LE- IMO.
The fact that they advertise "no BS" or "no games" doesn't mean that's how they work.  It's definitely something you want to hear, and those that post a rate schedule are more likely to be legit, but only having a number of reviews can really minimize the risk of a ripoff or an upsell.      
If you can anticipate the need a day or so in advance, you can probably find a provider in your area on this website that can take care of you.  Playing on CL is like rolling the dice with your ballz.  LE is only a part of the problem.