I patiently waded through all the pages of this topic.
I agree that what the perpetual 49's are doing (which I have personally encoutered on The Shadowlands) is not what was intended by the game design. I played DAoC which had an xp-off feature so you could stay at the battleground of your choice forever (Molvik was the favorite) and the feature has been present in many other games. The fact that the feature is not present here leads me to believe that Bioware does not expect you to be able to engage in normal experience earning activities and not advance towards your next level. Especially with the broad level range PvP bracket currently in place, which I think works pretty well overall.
The thing that I find most telling about this whole discussion has been the lack of attention paid to the effect on new players if this behavior flourishes. We want to encourage new players to PvP and to make it enjoyable for them so that they continue and the community grows. The demoralizing effect of walking into a Warzone as a new player and getting stomped can not be trivialized. While it could happen regardless, it's much more likely to happen if you have a great deal of "professional noob-stompers" on the other side. Having them on your own side won't matter, that won't be the experience they remember. Especially since the sub-50 PvP design encourages people to PvP at very low levels, the chance of having a good experience running into a decked out level 49 toon is pretty slim. If they have bad early experiences in sub-50 PvP, they are going to not participate in it, which means they will likely not participate in 50 PvP, and you have lost the chance to grow the PvP community.
If you want to gear up a lower level toon to have a gear advantage, that's fine, go for it, enjoy. But I would not be suprised to find that Bioware institutes a change that makes the ability to play warzones continually without gaining experience disappear.
Twinks were rampant in WoW looooooooooong before Blizz finally made twinking a "feature". If anything, BW will do the same here and have twink only Qs.
Anyone who is going to quit the game because they got stomped in pvp already has quit. You don't need 49 twinks on your team to completely stomp the enemy. Whiners like that never sub for any length of time--if they sub at all--and only add to more QQ on the forums.