The systems I've flown have definitely been altitude aware. They won't alert if the plane is sufficiently deconflicted above or below.
One problem for sure is that when you're close to the ground you have to be careful about buildings, cell towers, etc. Terrain is one thing, but when you're a few hundred feet AGL, you could quickly be in the way of tall structures if a TCAS alert goes off.
One problem for sure is that when you're close to the ground you have to be careful about buildings, cell towers, etc. Terrain is one thing, but when you're a few hundred feet AGL, you could quickly be in the way of tall structures if a TCAS alert goes off.