I've seen loads of diesels with V8 stickers on, not sure why they bother to be honest.
Maybe it's attached to the heater to warm up the water as it comes in when you miscalculate that local ford,...maybe.
From what iv seen petros dont take well to the wet regardless of snorkels. Maybe they knew that but still dident want to get cold sitting in that lake while waiting for a diesel to come rescue them.