Crib Scootin' - a game for babies!

Greta's crib has casters with wheels on it and it's constantly half-way across her room. She's a very active little thing. I finally had had enough of pushing the thing back to where it should be, so I purchased those caster cups - you know, the square (and sometimes round) things that are brown, made of a very hard rubber, which you place under the legs of furniture to protect the wood floors? My thought process was, since they have a "lip" the crib casters won't jump the lip and the crib will, hopefully, stay put. This morning found me on my belly under the crib struggling to get a caster cup under the wheel in the far corner. It was difficult, but I managed. Eventually I had a cup under each wheel. I tested it. No more than some minor wiggling!!! I'd fixed the problem! Quite happy I was...until Greta realized she couldn't scoot the crib across the floor anymore and screamed bloody murder! Man was she angry! She jumped up and down, rattled the rails, and tried to slide the crib anywhere but where it was - all without satisfaction. I've never seen her so mad! She was red in the face and screaming her little head off. Poor thing. It was actually quite funny. It had never occurred to me that she was scooting the crib across the room on purpose! I just thought it was a product of having an active baby! Well...she'll get used to it! TTFN JMS