Are PETRIS (Permit to Travel tickets) valid when the customer knows the ticket office is open?
4. Penalty Fares
Penalty Fares are charged by Train Companies at some stations and in some trains. You
may be liable to pay a Penalty Fare if:
(a) you travel in a train without a ticket or Permit to Travel; or
(b) you travel in a class of accommodation for which the ticket is not valid; or
(c) you travel in a train and the circumstances set out in any of Conditions 10,
11, 12, 18, 19, 22, 30, 35 and 39 apply; or
(d) you are present in a Compulsory Ticket Area without a ticket or Permit to
Travel
2. Requirement to hold a ticket
Before you travel you must have a ticket or other authority to travel which is valid for the
train(s) you intend to use and for the journey you intend to make.

For the sake of being pedantic, I'm fairly sure it's PERTIS not PETRIS.![]()