I have a K&M 3 leg stand too and although I've never had a problem with it, I prefer my "vintage" Hamilton trumpet stand that I got back in 1986 as a Sophomore in high school. The K&M is steady enough that it would have to take a pretty bump before your horn got knocked over.
For a short time I was using my K&M stand for my my trumpet and my Hamilton stand for my flugel, but I finally broke down and got a 5-leg K&M flugel stand and other than the fact that it sits so low and I have to bend over to pick up my horn, something that I don't have to do with the Hamilton (I'm lazy!
) I really like it a lot.