The warm-up ring has really been the only place I’ve noticed some degree of this, and again it depends which area you’re in and at what level.
The worst I’ve seen it has been at inter-regional championships where some local people might feel the need to assert their dominance in what might feel to some like a bigger pond.
My quirky old mare thrived in a program where I did two intensive weekends per year with a fantastic trainer from out of province, and spent the rest of the time doing my homework, so I competed on my own (but with a friend or family member to act as a ground person).
In-gates loved me because i was always ready on time and could slip into their spots while they waited for trainer conflicts or for trainers to give long lessons in the warm-up ring.
My ground people had no problem at local shows where everyone was friendly and knew how I operated, but at championships certain trainers from other regions would try to intimidate my helpers and get them to give up my jump. Thankfully they always stood their ground knowing I always directed them to stand at the jump when we were the right number of trips away (thanks to years spent as a groom), and I was happy to share if both groups needed a similar jump, or if they just needed to change it for a minute and then put it back to what I needed.
From experience competing at all levels and working in the show office at international shows, honestly the most troublesome barns tended to be certain local trainers trying to behave how they felt “big trainers” should behave at such shows, though the biggest names were usually the nicest to deal with and the most friendly.