The best advice serious professional trombone players give regarding storing your horns goes something like this:
I have never seen a trombone damaged by falling from inside its case.
In other words, the finest trombone stands on the market today are less safe than putting your horn away whenever you are not holding it.
But, I play them a lot less if I have to open the case, put them together, then reverse the process when I’m done tootin’ around.
Here is my compromise.
They are there for ready access and reasonably secure. Yeah, a 9.2 earthquake would likely wreck them, but they would be the least of my worries and probably wrecked in their cases anyway.
Besides, even when silent, trombones are fine art that ought to be proudly displayed.