This is a very odd exploit because it requires you to not really do anything but take talents provided from Blizzard.
Step 1: Be a holy priest
Step 2: Take the Honor Talents
A) Inner Focus (Can't interrupt you for 5 seconds)
B) Greater Fade (Can't Melee, Spell Damage, CC you for 6 seconds)
Step 3: Inner Focus >Greater Fade > Cap Flag > Get Reported
Just ran into this during a high rated RBG and once the Priest started capping as a Frost Mage base sitter I could do absolutely nothing to interrupt him. Not even melee.
Apparently some knockbacks and certain melee abilities will interrupt this but I have yet to see which. This is VERY broken. If you get a flag cap map with a Holy Priest just have them run around and do this. Free Win.
Abusing this will most likely get you a ban if reported a lot and considering RBG's are 10v10 you can expect any team that realizes you are doing this to get you 10 reports.