Offramp wrote:
From the February 2009 On The Move (No 155), page 18.

"A suspect who verbally abused a member of staff was identified thanks
to Oyster card technology.

The exact gate and time the suspect used a Freedom Pass was noted,
narrowing the pool down to a small number of possible holders. British
Transport Police could then pnpoint a single card, and therefore the
suspected assailant..."

Some good advice is also given: "...Touch your Oyster staff card on
the reader immediately afterwards if you get the chance - that would
easily identify the transaction before yours as the suspect's card."

I note that offering concessionary travel off-peak on buses is now the
law (although it would seem that offering them for tube/train/tram is an
additional "perk" in certain areas) and wondered if the operator or
issuer of the card has the right to revoke the card if the holder is
responsible for bad behaviour (like what is /supposed/ to happen with
the free bus pass for under 16s) and wondered if the same could happen
with the Freedom Pass.