Kicking out the boffins sounds like fun. Currently, we have not had any problem with ice thickness to support a B212 or an occasional Mil-8; however, we were informed by the customer that we need a written procedure identifying steps to ensure we are not exposing ourselves to unnecessary risk.
There is rarely a need to shutdown and once the ice starts breaking up and flowing, we do not shut down.
I'm assuming that some of the big operators who have worked in the Antartic or Artic may have procedures to ensure that the ice is thick enough, and other considerations.