I did wonder about that. I'm from a policing background - I thought it was a little unusual the conductor simply walked away up the aisle without even trying to challenge or advise the chap in question.
It is easy to judge other professionals through policing eyes when you watch these programmes so it wasn't intended as a critism.
The passive gentleman appeared to get away anyway when the conductor had to terminate the service at York owing to his decision to self isolate.
CJ
At the end of the day it’s just not worth the confrontation, and presumably if that part of the episode was filmed in March, there was also the added danger of Covid as you stated, particularly if a member of staff is spat at.
Not forgetting that the passenger did have a valid ticket to be on a TPE service between the destinations boarded, just one hour too early, so although he was morally wrong and travelling without a valid ticket, he was technically correct that TPE got the money for the entire cost of that ticket purchased (whatever that may have been), the value of the ticket might not be worth delaying the train for.