We had some significant wind gusts go through here last night and it blew my egg table off the patio. The end dropped about 6", but stayed upright.
The casters do not lock, but I had them set to make it difficult to roll in that direction and table, with the Egg weighs something north of 350 pounds. In the past 2 1/2 years, it has never moved an inch.
I have some cement blocks in front of the casters now.