I have carefully thought about this issue, and have concluded:
TICKET BARRIERS ARE A TOTAL WASTE OF TIME
They cost the TOC's or SOC's (station operating companies) millions of pounds, and the process of construction is timely and causes overcrowding at the station entrance/terminal.
After installation, the majority of the time, especially at Exeter St Davids, they are manned. This is a waste of time, the companies using up even guards and station train dispatchers to forefill this role.
Another thing is, at occasional peak times, Sundays, evenings and early mornings, these arn't manned nor in operation.
Like previous mentions, they are completely unreliable and break every few weeks. Repair is again timely and costly.
One major question is of course why the hell do you have these ticket barriers?
Train guards appear to be present on all journeys around the South West, so is the role of the conductor being changed? Will these workers soon axe walking through the carraiges collecting tickets, or are these barriers absolutely pointless.
Trainspotters must have a hard time accessing the platforms of these busy an enthusiast attractive stations, so what are the enthusiasts to do? - I propose a pass should be valid for the enthusiast to access all public areas of the rail station, and, if trains are to remain manned for the future, they can be issued a simple fine if trying to travel for free.
But, if this movement is acted, it should be free of service. Almost a right. Why should they charge a toll for this privalage? It should just be "Get yours at the ticket office" or "Send off for yours now".