Is there an (un)official rule about twisting back a seat on broken bike for CitiBike or other shared bike programs? "don't pick a bike if its seat is twisted around backwards. That's a sign that a previous rider found the bike busted." -(from SamtheBrand's answer to How to choose the right Citi Bike? )


Can someone please elaborate on this rule please? 

Is it widely known and used?[1] 

Is this some sort of official or unofficial rule communicated somewhere? 

Is it specific to Citi Bike program or generic to any bike rental/sharing ones?

[1] - I have ridden Citibikes almost every weekday for over a month in NYC, and have never observed a twisted-around seat. But I didn't set out to find one so it's not much of an evidence.
This appears to be a widely-used, but unofficial way of communicating that the bike is broken and should not be ridden. See the Wired article that documents this trend: "Courteous Citi Bike Riders Are Alerting Others to Broken Rides" by Christina Boddington.

Also, on Twitter, you can find numerous examples (many of which were cited in the Wired post).