Birmingham Anglers Association

I do fish for salmon and so would try to clear this up a bit if I can, but there are grey areas.
During the coarse close season you can only fish for trout and salmon on the rivers. On the Wye, as most rivers, that usually means by lure or fly only. The Wye (last time I checked) was fly and spinning only from 3rd March up till the end of the season on 17th/25th Oct depending of whether or not you are below or above the Llanwrthwl Bridge - so officially you should never target them with prawns or worms. But, as you say, who is to say you aren't fishing with these baits for barbel or perch during the coarse season - big loop hole there.
Some coarse anglers will fish with lures during the close season for trout - non-migratory trout and salmon need an extra licence, of course - which I pay for. But it seems many don't bother, simply claiming they are fishing for brownies - if they catch a salmon or sea trout 'by mistake' it is catch and release anyway - so I fail to see the incentive for most to pay for a much more expensive salmon licence if they only use spinners. Of course if you use a double handed spey rod for fly casting, as I do at times, it is pretty obvious you are after salmon, so you'd be a fool not to buy a salmon and sea trout licence.
I do see lots of anglers spinning for brownies on some of the BAA rivers during the coarse close season, and, even though they are legally allowed to do this, somehow it seems wrong; simply because there is a high chance of hooking a pike, perch or chub during their spawning period - I tend to fish fly only during the coarse close season and because of the style of fishing doesn't seem to catch coarse fishing, except in the warmer months.
The Alne is hit badly by poachers doing this fishing during the close season, groups of young lads usually, so I'm always nervous to attempt to ask for their membership cards in case a filleting knife is put to extra use!
I checked the link you posted but couldn't see the references to not using trebles, but this would help protect fish. Many of these 'trout fisherman' use shop bought spinners (Mepps usually) which only come with trebles, unless you cut them off and use a split ring to put on a single, which I guess they will have to do now. I guess also salmon flies are still allowed to use doubles but will have to check the new rules myself.
Hopefully that clears it up a bit.