I always thought CARES was so much easier then the car seat. I did the practice at home on a kitchen chair, our extra length was in a rubber band. And it has never interfered with the person behind us. I do agree the lack of a crotch strap allow sliding. I never got around d to making one for ours. If you think your kiddo will sleep, have a good pillow or blanket for them to lean on. That was the one plus with sleeping in the car seat, their head has decent support when it turns to the side.
While it is a pain to rent car seats, I would never be comfortable checking one. The rough handling could subject it to the sort of impact that could compromise the integrity of the seat. If you read the book with your seat, it will talk about checking the integrity of a seat after a crash. You have to looks at red threads on the straps in a certain area and see if they are torn.
As someone mentioned before, unlike in a car, the main concern with child safety on a plane is not a forward impact but a drop type occurrence. Small children could slide up and out of a seatbelt (or your arms) hence the CARES going over their shoulder. This is why we have always bought a seat for our child even when she was still considered "lap". Other then infants that can't sit in an upright position, being rear facing is not as important for older kids on a plane. We used our Britax for DD at 11 months and it never would have fit rear facing. she grew out of the largest carrier type at nine months.
I have never had an issue with anyone being bothered by the CARES harness. We had a really grumbling FA once that hassled us for her ticket, the label on the Britax, and then when I took her out of her seat mid-flight to check for a dirty diaper (seat belt light was not on and I agree with the never buckle them sentiment) she came by to tell me that "if you have to have that think on the flight (car seat) she has to be in it. Grrr. And when I say hassled us, I think it is good for them to ask for all those things, it was just the way she went about it, like she was disappointed we knew what to do. But that was just once of the many flights we took and maybe she had a bad day or a bad experience with people who didn't take the time to figure out the how it all works.
