...cuz I'm just a lurker buuuuut, from everything I've read, bonuses from a ring of protection +2 and a cloak of protection +2 would
not stack... Now, if there was some even minor difference between the two - a ring of protection +2 and a cloak of protection against evil +4, for example - the "basic" protection bonuses still wouldn't stack
but the cloak would provide an extra +2 vs evil beings.
Again, I'm not a rules lawyer and
would likely allow the cumulative bonus as part of a "house rule" or something but that's just because I don't particularly care for the "limitations" (why give the item away when it's going to do nothing, right? Bonuses should either stack
or, conversely, the enchantments on each should be made to conflict and "cancel each other out" (magic is a quirky thing, after all)... But, like I said, I'm no DM, nor am I a rules lawyer or exceedingly well versed on the workings of magic... Feel free to ignore me.