Like so many other things in life its not a question of what you do but how you do it.
I'd be all for barriers but only if the following conditions are met (and they never are)
1) all tickets sold are the right size for the barriers
2) they are used in the evening when the chavs are out (otherwise the justification that they reduce antisocial behaviour is weak)
3) there are loads of them so that they don't cause queues
4) they do not retain tickets but merely cancel them (so tickets are available for compensation or company expenses claims)
5) there are realiable (and staff are instructed not to clip tickets across the magnetic strip)
6) they are not used as an excuse to reduce on-train ticket checking (i resent it when barriers are installed for the reasons that
FGW▸ don't trust their staff to check tickets on trains or because the trains are too-crowded for an on-train ticket check)
7) there are always suffcient ticket machines and manned windows.
they do not reduce access to the station (for example the barriers at Bath mean that customers coming from Widcomb have to cross the track via the underpass to reach the barriers and then cross the track again to reach platform 1. this adds a couple of minutes to their journey)
9) the barriers are sophisticated enough to let you out of the station and then back in a few hours later. (so for example you can buy a Paper from Smiths at
BTM▸ between trains)
10) the barriers are correctly programmed (for example the Oxford barriers are programmed to reject certain tickets at peak times and are unable to descriminate between valid Oxford to Bristol tickets and invalid Oxford to London tickets and will reject both)
11) disabled and pushchair access is maintained
12) platform tickets are available so you can help friends onto their trains (afterall porters have been abolished)
13) platform numbers are acounced in good time (not like at Paddington)
14) they do not lead to overcharging (as is the case where Pay as you go
Oyster▸ has been introduced on the London Overground - cheaper tcikets are avilable on trains after 9:30, but if you travel on the 9:31, and touch in at 9:29, you will be overcharged - possibily illegally)
My objection to barriers is not that they are bad
per se but rather that they are implemented in a cack-handed and customer-unfriendly way