Similarly, I know people that don't want to eat in the dining room or alternate dining rooms at all. They prefer to eat at the buffet (e.g. in jeans or shorts, it is much faster). This should be an option when you reserve your cruise, i.e. no dining in the formal dining room. This would make planning tables and staffing much better.
Buffet dining is becoming more and more popular. We were seated at a table for 10 on one cruise and we were the only 2 that showed up! Eventually they assigned diners to us that wanted to change time slots. We've gotten to where we eat at the buffet 1 or 2 nights a cruise simply because it is so much faster and we have a lot we want to do.