The trainer I work for allows visits, if previously planned and organised, drop in visits are not at all tolerated and we always like to know exactly how many people we are catering for. We have about 100 horses riding out every day - could you imagine the chaos that would ensue if several groups turned up at the same time wanting to see their horse work? In a large establishment, routine is everything. If there is a hitch in the daily schedule, it throws the entire yard off, not just that one horse.
As to is reasoning behind not allowing other visitors, I don't know. Maybe it is due to time restrictions, maybe it is for security purposes? If I owned a large yard I wouldn't want random people wandering around - I say there is plenty of tack there that is worth a pretty penny... and then you'd probably find some animal rights nutso who wants to have a hissy fit because ol Teddy in the stall on the right is resting his leg - and in nutso's head the leg is obviously broken.
The girth galls thing - I've seen them on riding school ponies. I've seen it on hunters. Over the years I've seen it on all shapes and sizes. These things happen, it is not something that only pertains to CA, so I'm not quite sure why it is adding fuel to the fire. This is getting to the point where it's just a witch hunt where people are feeling the need to throw everything at the kitchen sink at him. You can't really compare CA to the everyday trainer down the road - if this happened to that trainer would this even be up for discussion at the moment?
Stop for a minute, open your mind, learn. You may not agree with what I say, I may not agree with what you say but we will both learn something new.