A recent fatality of a public service diver has made me stop and think about this.

He was floating behind a boat without diver gear donned in about 20ffw. His neckseal tore and the suit flooded instantly sending him to the bottom of the near zero viz river. I have often floated out into deep water in a sink before or after a dive. I will certainly be aware of this possibility in the future. Just something to think about.