I would use lids myself, it is just that I lost my soldering iron to cut the holes in the lids, so I go without. All that is left is more water spills to clean up, which in turn is a higher cost for subtrate.
I think that this death of the Grey-banded is a relatively rare occurance. I know many folks that use this method for literally thousands of snakes with never having any ill effects. It is just that a snake that cannot figure out a way out that has the misfortune or chance of drowning.
To those that made a big deal about it, realise this is a very rare problem. I know Kerby Ross (Lonesome Valley Reptiles) uses this method for his large collection, a buddy of mine in CO uses this method for hundreds of snakes, and many many others. This method has proven to work very well in husbandry over the years in many collections. Everything has risks if you take the time to find them.