What else should I do if cannot record them doing the karate techniques...

[daniel]

...when I attempt/or maybe like? recording them doing the techniques there?

Other to do: Search other karate video on You-Tube, Camcorder that's small like a box or with much lesser pixels, etc.

Or any other ideas you have that might be different from these?

[Frankthetank]

Easy.

If people don't want you to record them, then don't.

Here's another idea: get another hobby.

[kokoro]

If you want to learn karate then join a class, otherwise you are wasting you time.

You should consider yourself lucky I know a few schools that would have thrown you into class and taught you a leason.