BART Station Agents Enforcing Bikes on BART Rules?

Reader Chris sends us this note:

Did anyone else encounter the BART station ticket agents enforcing the no bikes on the East Bay bound lines this morning?  The ticket agent at 16th and Mission was posted up at the bike gate asking everyone with a bike which direction they were headed.  I understand the rules regarding bikes on BART, but this is the first time I actually saw a station agent in the Mission enforcing them.

Annoying, at best.  I’m sure there is a legitimate reason as to why they have not done this, but why don’t they dedicate one car during peak hours to be a bike car?