In message 01c383a8$214dd840$d405e150@default, Michael R N Dolbear
writes
As with retention of mobile phone call data, the possibility of the
data being useful to prove an alibi ("and then I went straight home")
never crosses the 'minds' of Civil Rights Campaigners.

Because it can't "prove" innocence. You might have lent you phone or
Oyster Card to someone else. But as a strong indication that you were
near the scene of a crime, it can draw suspicion upon you.
--
Roland Perry