There are differences, I understand, between 'marine' and 'aviation' liferafts - and it's not just price. Aviation liferafts are required to vent to atmosphere in the event of a fault. Marine not so. Therefore to carry a marine raft in the confined space of a light aircraft might just provide the excitement of a lifetime if things go horribly wrong and spontaneous self-inflation occurs. I use an aviation liferaft but I also carry an open pocket-knife ready to hand at all times over the water. Just in case.