When I use the Birdy for commuting and shopping I replace the seat quickrelease with a hex bolt and secure it with HexLox (I do the same with my wheels). This to prevent some idiot thief from stealing the seat & seatpost (it won't be worth much to them, since it's a size and length very few are interested in). For shopping it's quicker to leave the bike locked outside, than folding it and bringing it inside. On tour however I mount the quickrelease, and bring the folded bike inside my hotel room at night. But then the seatpost is vulnerable when I stop for shopping food for instance.

Has anyone come up with a way to prevent seatpost theft while using the standard quickrelease? It doesn't have to withstand heavy tools and criminal masterminds, just quick attempts by opportunistic idiots. I was thinking to make a plug that's too big to go through the seat tube, and attach it to the seatpost end plug with a wire. It would sit invisibly in the hole down by the bottom bracket. Then you can't pull the seatpost out, and the opportunist thief is hopefully frustrated enough to give up and go away. When folding, the seatpost knocks out the plug and it hangs from the wire. Maybe if I add a magnet to it I can snap it to a steel bolthead so it doesn't get tangled up in anything.