I scheduled an appointment with a fairly reputable k-girl agency. We had some back and froth text messages. The scheduler asked me if I wanted GFE or GFE+. I was hesitant to respond but finally did and said "plus". Thinking about it now I know that we are not supposed to talk about any "services" and that money spent is just for the ladies time. Do you think talking about GFE was wrong? Can I potentially get busted for this?

If you want to be safe beyond reproach, then don't go through with this, but I very much doubt that anyone has ever been found guilty based on evidence that they used the acronym GFE with or without a +, or for that matter just about any acronym.  After all, these acronyms were invented for the most part to try and avoid using frank and therefore presumably illegal speech when setting up our rendezvouses.  

GFE and GFE+ have no legal significance

For someone new, I'd steer away from any discussion of services, esp in print (email or text).  If there is a difference in donation for GFE and GFE+, you can always settle that with the provider when you are BCD with her.  Personally, I would be reluctant to mention anything in relation to different types of visits, but that's just me.

Looks like I got me a stalker.  Take a picture, it'll last longer.

"GFE" and "GFE +" absolutely denote specific sex acts and are therefore incriminating. People have been busted many times for their use of such acronyms. Please be careful when dishing out legal advice.

Interesting.  Any evidence of this you can share?  I'm always willing to learn.

Is anyone aware of the prosecution ever using email evidence against a client?

Using acronyms like GFE, CIM etc are most definitely incriminating, there is no "code" that allows you to discuss sexual acts for pay with impunity, just like there is no "LE check" that allows you to identify uncover cops. LE and the courts are perfectly aware of what terms like these mean and no they will not help you even in court, much less keep you from getting arrested if you unknowingly use terms like GFE in a conversation with an undercover cop. This goes for both hookers and johns alike. DON'T DO IT

To a news story about prostutution arrests. His post was pulled because the news link had real names. TER does not allow real names in posts, including links. You keep asking for proof but people can't give you proof, because of TER rules. You can probably find your proof just by googling though, or maybe you can nicely ask GaG by PM to send you the link. Anyway, I read the link before it was pulled, and these guys were arrested based on using terms like "GFE," and "full service."  
As several here have mentioned, newbies (and even veterans with no legal background) should refrain from giving legal advice.

I saw the link and read the article.

In any event, just because some providers offer services that need to be established ahead of time doesn't make it legal. Hell, escorting in general is a massive legal gray area, so the idea is risk mitigation, not risk elimination.