Depends on how much the spacer moves while carried in some mag pouches. I haven't had a lot of trouble with it, but my extra mag will always show that spacer tipped a bit away from bottomed out on the mag plate. It conceivably could result in a failure to fully seat a reloaded mag when done under stress, and that's something I don't much like to leave for chance. And the spacer does lose a small bit of it's original tension over time when it's carried daily around my waist. Probably because my love handle puts more pressure on it than some of you skinny guys do! Even if it doesn't bother with seating, I just like the looks of the thing in its proper place on the mag. You could completely remove the thing, but that really doesn't look to good, either on a spare mag or when that mag is seated in the gun. Doesn't feel too good with that spacer missing either !
Since the spacer can be held in place without a lot of mess (if you are careful with the black ATV, and since the stuff is pretty easy to clean up and off if you wish to do so, it seems to be an acceptable way to "fix" this situation.