Take it from a guy who, as a teen, rode his unicycle everywhere (I even delivered the newspaper on it). The joke that we (owners) will hear is..."Hey buddy, you lost a wheel!" Followed by the roar of self satisfied laughter. Everyone seems to think they are the first to think if it.
Guy on Youtube drove his Morgan 3 wheeler across America, guy pulls up next to him yelling "Hey Buddy, you lost a wheel" of which he had heard a thousand times.
'Yeah, yeah, I know"....
"No Buddy, you lost a wheel!"
Gives him the finger, so the guy takes off.
Next petrol stop, he sees his SPARE WHEEL that was strapped on the tail has gone, lol :-)