I do wonder why FCC put staff on gates so early. I guess they need people to open the station, unlock the waiting rooms and so on - so if they're selling tickets from 0530 then they may as well have the gates in operation, but do they need the gates working then?
Ignoring those with or without tickets, how many people are travelling full stop in the morning? The first train at Hatfield is around 04xx (can't remember exactly) and the station building isn't open then (the side gate is left open from the last train around 0204). You might have some people going in to London early for a flight, or shift workers, but not much else. The train used to be for staff only, but makes an excellent service for early flights as by the time it arrives at King's Cross it's only a few minutes to wait until the tubes start and HEX begins.
Then there's a gap until the next service of quite a bit, and I am not sure if the station is open by then. But, it would still be pretty empty if I had to guess.
Now, the further out you go the earlier people will begin travelling to get into London. But, few people are getting on between 0400-0600 from a station only just outside the M25. You get in far too early, and so I doubt that many people are going through London and back out (some, obviously, but not many). Are those people likely to fare evade if they're going in to London to get an early IC train? Maybe, but wouldn't it be less than those getting a free ride at night?
Perhaps FCC could man the gates later, from say 0630 or 0700 at the stations on the suburbs and then keep them open until 2200 or 2300 (but I'd be thinking of 0000 as it would catch those coming back from the pubs).
At KGX and FPK, where people will begin most of the journeys home at night, they should at least have both of those stations with operational gates from the first train and until the last train has departed.
If you assume everyone will simply buy a ticket to the next stop, you make sure that you frequently have revenue officers on these late trains instead of having them disappear too - bar a few occasions where they seem to have stings - and you punish people accordingly.
Gates can't work on their own. Revenue officers can't operate without gates. For most of the day, FCC has a decent set up but they let it all go by deciding to open the gates at between 2000 and 2100. Sometimes even earlier on a Friday night at Hatfield (presumably due to staff shortages) where the whole building is closed early, meaning no gates and no open ticket office: a good way to encourage people to just go out on Friday night without a ticket at all. FCC won't even manage to restock the TVMs with ticket stock all the time, so I've seen a Friday night (at 1930) where the station is closed and both outdoor TVMs are 'OUT OF SERVICE'!!