I also check for a life jacket but really think they are a waste of space, especially for an open ocean ditching. Aircraft used to carry large dingies that could accommodate 30+ people. Four or five would suffice for most aircraft. Initially these were open with buoyancy chambers. Then a self-inflating canopy was added which would give you a secure and warmer environment and a real chance of survival. Ships still use these.
Now, with over 300 passengers you would been 10 or more dinghies. Most passenger aircraft now use the door escape chutes as life rafts. The approved way of using these is to hang on in the water until you die.
Modern aircraft have ditched and everyone on board has survived. Usually they had survival suits and proper dinghies.