Everything I read about it says it’s primarily spread through the mouth while coughing and talking. I also have a big nose, and the pressure from the mask makes me sneeze when it’s covering that nose. People might not like it when I leave my snozz uncovered, but I imagine it’s safer for them than repeatedly sneezing with my mask on properly. From my experience, if they’re wearing it that way in public, they’re going to take as a confrontation no matter what you say. I learned that the hard way at my own micro-wedding last weekend, trying to say this to my own mother and nearly started a brawl.
Ask them if they’ve made their funeral arrangements while looking at them like they’re a piece of juicy steak and loudly licking your lips behind your own mask. If they object, just apologize and say something to the effect of “Your mask was down, I thought you were offering…” Make sure to keep uncomfortably direct eye contact the entire time and be as “otherworldly” as possible. Use a voice that’s just a “little off”, and be sure to let “offering” trail off and hang in the air. Let them wonder just exactly what you think they were offering.