Quoted from ShinyBall:
they make these for the reason of nudging. Damage control.
and it says in the description quote: "Every time a player "nudges" your pinball machine to try to save a ball they are putting pressure where the legs meet the cabinet causing the legs to dig into the cabinet PinGuard™ protectors save you all the worry of any damage occurring to your cabinet while your "friends" push it around the room trying to save their ball."
Again, Nudging is fine..it's the over aggressive people that make legs loose, decals around the legs wrinkle..and how many times have you seen a cabinet with "bondo" where the legs attached. Cabinet separation at the seams. Over zealous players.
Sorry, not on my machines.
If the decal wrinkling part worries you, why are you not using some kind of leg/cab protectors, just in case someone is a bit over-motivated? Actually, after some years in this hobby i've never met anyone not using protectors.
My machines are usually either re-decaled or have very good original decals. The pins are nudged, slap saved and even slide saved heavily and there is no sign of decal wrinkling at all.
I also don't use any kind of casters under the legs as they kind of "stick" the legs to the floor shifting the complete pressure from nudging from the leg/floor connection to the leg/cab connection. The legs need to be able to easily slide on the floor, otherwise you are unnecessarily stressing the leg/cab joint.