I used to work for Dogtra, which is the e-collar most hunters use for their retrievers and the police K-9 units. I used the smaller collar on Monty to no avail, but the larger, more high powered one worked better. I would NEVER do anything to hurt my boys, and since I worked for Dogtra, I was able to test all the collars- on myself. I've actually put the collar up to my neck and stimulated myself... What I described the stimulation to my customers was- It's like wearing socks, rubbing your feet on the carpet and then touching the door knob. It scares you initially, but it's not torturing painful. It's probably the most annoying thing ever...however, there are people who just turn it up to the highest level and just...SHOCK.. .which is TOTALLY abusive. I think it has to be a very aware person to be using this sort of training. Be careful.
I believe that if your trainer is not giving the dog the appropriate collar, and not giving you proper instructions-you should definitely talk to her and just let her know how you feel. See how she handles it-if she gets defensive...we ll that's really not a person you want e-collar training your dog.
Good luck hun! You're not wrong, you're concerned, and you know Titan better than anyone, if your intuition says something, listen.