It only takes a couple of mods. First you need some coffee, coke, kook-aid, something sticky, apply to the A/C vent and make it hard to move. I prefer the running late and spill it everywhere method.
Let dry a couple of years. When your A/C vent will no longer move, you have a pipe holder
Let dry a couple of years. When your A/C vent will no longer move, you have a pipe holder