This is a trick I've been using to capture Stables at the beginning of every Arathi Basin I play on my horde. This requires that you are an engineer. Enchant your helm with the Tinker: Mind Amplification Dish.
The trick is to find a node defended by only one enemy player (this is key), stand next to the flag, mind control them with your helmet, and then cap the flag. If they don't have a way to dispell the MC, then they can't do anything but watch as you cap their flag. The timing works out so you should have a lit of wiggle room between you finishing the cap, and the MC ending, but not much, so I'd recommend keybinding the MC and immediately starting to cap once their mind is under your influence.
Hope this helps!