Kitchen sink stoppers

This didn't seem to fit anywhere but I did want to discuss it.The houseman who services our room was always leaving the kitchen sink stoppers in the pushed down position after cleaning the sinks. I never asked him about this. I was, however, footloose and fancy free with how I left the kitchen sink stoppers--until I read the reason behind it in some of my literature on living in Indonesia. It's not as important in a high-rise apartment building, but in a house, leaving the sink stoppers down prevents a variety of critter from crawling up and out of the drain! In the apartment, about the only thing we'd get would be a drain fly. And I think I've seen a couple. Now I try to remember to push the stoppers down when not in use.