I've seen horses try to flip over in crossties, some that pulled back against regular ties, some that couldn't abide trailer ties .... your mileage may vary.

My Walker mare will let me clip her (ears, fetlocks, bridle path ...) loose in her stall or even lying down. I generally just quick-release-tie her to a hitching pipe. I like to use the crossties when I have to stand in front of a horse for worming or teeth or whatever, or when I have to do the hooves of a horse that won't stand calmly. I'm boarding the mares right now. There are 8 crosstie positions, two stock washracks, one hitching pipe wash area, and another hitching pipe. There are a lot of lesson kids running through all day, so an unsecured horse is a real hazard. We'll be moving to a better place in May if I can get the TB on the trailer (another phobia), so I'll try to get blocker ties installed there.

The TB is very much the idiot savant. A few months ago she pushed over the girl who was unbridling her and ran out of the barn, dragging girl and bridle. The girl soon let go but the bridle was not so fortunate. For some mare reason she ran back into the arena and cantered around in the sand. My new bridle was split through the crownpiece. Better the bridle than the leg, but I couldn't afford it in the first place so it kind of hurt to lose it. I don't normally have leather tack, and in this case I'm glad it was leather. The very next day we found that not only will she free longe, she will follow a person at the trot around the arena, even over cavalettis and through a trail pattern, as though the person were holding a lead rope. She even executed a perfect rotation in the box, which my other mare can never manage.

How do you attach a blocker ring to round pen, or are you not using pipe pens?