BS and more BS. Anecdotal evidence can sometimes be the result of confirmation bias. Perhaps not in all cases but I would have to see far more real science conducted before believing just about anything on youtube or from a 'pro' with an investment in promoting a product or theory related to a product or a better product.
I lean more toward what others noted above, that some cams make noise. I had a series of cams a few years ago that often seemed to catch the first photo of a deer while it was looking directly into the camera. This was usually a deer relatively close by and almost always at night in infra-red mode which made me think the cam 'spun up' in some manner right before snapping a pic. I'm mostly deaf now and I couldn't hear it if I wanted to so maybe there is something to that theory.
My own experience does not include cell cams because I personally do not need them nor feel that users, in general, can be trusted to not use them in unethical taking of game. I have anywhere from one to eight standard card-cams out on my property depending on time of year. Through the winter and up until about now it is one or two cams and I swap cards every day... every day. They are three to four feet off the ground and I have mature deer, both doe and buck within feet of each, daily. They do not care and the cams definitely have my scent on them as I go out over my lunch break (work from home) to get some steps in and walk some trails.
One of the greatest piles of BS in recent times is all that nonsense about how you now suddenly need to buy copper lined clothing to kill deer because they can sense your electronics and your own bodies electrical system blah blah blah... how about scent control people?