We use them all the time at work for full size school buses. Never an issue as long as they are in the appropriate position and have the correct weight rating for what you are supporting.
From the OESC
6-312 Condensation in consumer’s service raceway
(1) The consumer’s service raceway entering a building shall be sealed and shall be suitably drained where it enters the building above grade level.
So yes a drain hole has to be drilled into the bottom of the LB.