Normally I'm pretty diligent about party guests' dietary issues. In the past the only issues I've run across were a few vegetarians and one with shellfish allergies.
If, say, Sloppy Joe's were on the menu, I'd buy a package of vegetarian "meat"-type mix and make a separate batch for the vegetarian guests. For the shellfish allergies, I make a few really nice shrimp/crab dips but I'll use the same ingredients sans the shellfish and clearly mark the difference . . . these are just a few examples of how I try to accommodate those with dietary issues while at the same time sticking to the menu with dietary variations.
At a recent party that I hosted, Emily (one of DD#2's friends that I don't see very often) showed up just as I was bringing out a hot Rueben dip to the buffet table. We gave each other hugs, It's good to see you again! Blah blah blah.
Then she said "That looks really good. Does it have meat in it?"
Me -- Deer meet headlights. Oh, yeah, she's vegetarian
: Yes it does. But there's (the standard) veggie tray, chips/dips, cheese and crackers for you.
Then I felt really bad bringing out the meat-stuffed mushroom appetizers (which a few could easily have been changed for vegetarians). Along with not having a vegetarian hamburger type of thing when the main entree was steaks.
For the main meal there were two types of potatoes (mashed & scalloped) 3 veggie dishes (corn, green bean casserole and roasted asparagus) dinner rolls and a very large garden salad.
Emily was very gracious, but I felt bad for not switching some portion of the appetizers to a vegetarian style, especially not having a veggie-style main entree available.
Was I a rude hostess for not remembering Emily's dietary preference?