Sometimes the best thing isn't the most comfortable one.
Sometimes the best thing isn’t the most comfortable thing.

If you read enough sea related incident reports you will notice that there are incident reports about people who probably did wear PFD’s or even a proper life vests but still drowned and found without PDF or vest on them. How is this possible? In some cases they just slid out of it. They did not have or did not attach the crouch strap and when hypothermia set in they were unable to hold their vest into place. With PFD’s not having such strap this could happen to you in an emergency situation.  I already posted in a reply to some FB post about adding such strap (not to have it on while paddling as it would irritate your bum, but something to attach when in water and no self-rescue options available), but I won’t see that happening soon. But luckily most seakayakers have either a vest with cowtail or tow lines and they could save your live. In case of the cowtail it’s pretty simple. Detach it take it under your legs and attach it to the highest point on your vest without getting really uncomfortable and this will keep you from sliding out of your PFD.
In case of the towlines you will have to shorten it by a knot and after doing so it will work the same.

Note: I demonstrated this with my Astral PFD. Just want to make clear that I never involuntary fell out of my Astral PFD.