i am cat-sitting for a couple of weeks.

one of the people i am doing it for has given me a month long travel card which expires in a weeks time (he's gone on holiday) so it comes with a photocard.

if i was to use this am i right in saying that i would have to show the card everytime i was exiting a tube station ? i couldn't just put it through the machine ? meaning that i would at some point get found out

and i guess this^ would lead to a fine ?

thanks.