Not that it would cost anything to beep it, but any inspector who
didn't understand about travelcards ... mind you, an SWT guard within
London told me that a travelcard could only be used on one NR trip, and
insisted on scribbling his mark on it (a paper one).

Been there, got the T-shirt (it's blue, if anyone cares) Bought an OP ODTC
in the morning, went to London, shouted at a few people, then headed home.
The problem that I had arose when I got off the train at Portsmouth &
Southsea, and asked to retain the ticket as "I'll be back in London later".
The RPI assumed, incorrectly, that I wanted to re-use the ticket to get a
later train back to the capital, whereas I was actually getting a lift back
up. A bit of head-scratching by the RPI at Portsmouth ensued, until I
actually said "why don't you just scribble something like 'valid within
zones 1-6 only', so I can't use it before I get back up there?". "Good
point", he said as he scribbled on the ticket, smiled and handed it back to
me.

M
Portsmouth