I had a similar thing yesterday - one of the building maintenance people told me I can't bring my bike in the building (2 or 3 people including myself have been doing it for years... it's a 9 story building with 5 elevator shafts - not exactly crowded) and "didn't you see the memo from 2 weeks ago?". He was only around because there was water leaking into the cube next to mine from the ceiling...

Anyway, I talked to 2 of my seniors (who are employed by the same party that leases the building) and they were flabbergasted (I bike with both of them occasionally on weekends) and confirmed they'd seen no such memo, and said to ignore the guy. So I did. There is a garage with a rack downstairs but I don't want to lock up my bike. If I have to I can.