Good podcast. I always hope that the DM will ask the players if there are areas of play that would make them uncomfortable. The players can tell the DM then or talk to him/her later. If I am in a one off with a bunch of people I don't know I just assume some stuff will be off limits. I do write spiders and snakes into my modules. You are supposed to get scared. But for some people even in game spiders are more than they can bear.

Yes, it's basic courtesy. Not everyone has the same experience or able to ignore thing.
For example, it doesn't bother me to discuss gross things while I'm eating and sometimes forget if it comes up in conversation during a meal. I should have used that example in my podcast.