So interesting answer on the Dexter FAQ site. Take it for what it is worth.
E-Z LUBE - What is the E-Z Lube option?
The E-Z Lube option was designed specifically for the marine application where the axles are constantly being immersed in water. This feature provides a convenient method for purging the water from the hub cavity without having to pull the hub every time. The hubs should be removed every 12 months or 12,000 miles to inspect the bearings and it is imperative to replace the seal at this time to assure that the grease does not leak out the back onto the brake linings rendering the brakes non-functional.