Had a gig on Saturday and stacked one Kabinet on the other ( as you should). Seems stable enough but couple of songs in, it fell off! tried agin and just managed to catch it mid song. Had to put both on the floor mid gig...
Why did this happen? Initially I was really confused as they feel very stable....turns out it was due to a dodgy stage ( bouncy!!) and lots of bass coming from our bass player....so no criticism here as on firm ground they are rock steady, but I guess a small minor disadvantage with them being so light and portable :). I was more concerned it was damaged but no issue.
Otherwise sounded great!!
Moral - don't stack any cabs on a dodgy stage!!!!!