You should work it out with the trainer when you're not comfortable with an exercise or specific introductions. A great trainer will always accept your opinion and find a other, creative way to get you to your goal even when it takes more time and work. If not you should go. Never do something that dosen't fell right for you and your horse.
I say take it in! You may not agree with everything they say but you will hear pieces of knowledge to put away and store for yourself. Always let someone explain their reasoning for things, so if you don’t agree them ask why they would do it that way instead of another way. X
You do what they want for the duration of the clinic. You can do whatever you want before and after the clinic, but during you’ve paid for their knowledge and experience so do it their way.