Firstly, I'm pretty sure there would be zero grounds for such a lawsuit. I'm not forcing anyone to play the map, nor are they paying me for a product, nor is it broadcast over government-regulated airwaves.
Aside from that, are you seizure-prone yourself? Or has someone who is mentioned it to you? I admit I'm not all that knowledgeable about seizures but the trains are nothing at all like things I have seen marked with warnings. I just wonder if there is a basis for your request, because I feel like if something happened to someone on your server you would have mentioned that.
Saxton Hale... I'm not about to release an update just for that. Shouldn't the mod handle that anyway? Removing all func_respawnroomvisualizers from a map seems like something that should be done with the mod code so that it can be ran on any map without editing the map itself. I'd actually suggest mentioning it to the people who make the mod, as it would end up with support for more maps.