I had a wasp go down the back of my shirt while on a motorcycle. I also had a large fly (bluebottle) go into the back of my mouth. I couldn't spit it out because it was so far back, so I had to swallow it. Glad it wasn't a wasp because that's likely to be deadly if stung in the throat. Then another time (still on a motorcycle) I left my helmet on the ground next to the bike. While riding home, that evening, my left ear began to tickle. I knew there was something in there so I stopped and removed my helmet. A blonde caterpillar was crawling behind my ear.
Even on a bicycle we almost need something like a gauze mask to keep bugs (wasps?) out of our mouths.