If I put the zip ties very tight, there is not too much movement, unless I'm not careful when I put the bottle in. But I found that if I install a piece of double-stick tape under the cage, there is no movement.
However, I should add that I use plastic cages (Profile Kage). My first reason for them is that they don't mark the bottles. But for the cages that are attached with zip ties, the added bonus is that the plastic won't scratch the bike paint if (when) they move. If I were attaching metal cages with zip ties, I would wrap the metal tabs with electrical tape so they don't scratch the paint.