im pretty sure snakes cant choke by swallowing a piece of bark seeing as they swallow their prey whole everytime they eat. that's what the glottis is for. the worry with BP's swallowing their substrate is impaction, but i also dont think you have to worry about that because they digest the bones, hair, etc. from their prey everytime they eat.
EDIT: (me and xdeus posted at the same time, thats why it says basically the same thing)