Anyone else fallen victim to this yet? I do it at least 1-2 times a day... go to click an item in chat, but due to the crazy "hit box" of the item links you have to click in a very specific area to actually pull it up, otherwise you just click on the world somewhere and make your character move. Accidentally clicked the obelisk instead of item - character moves over and rift is immediately opened without confirmation. Of course you have to clear it now!
Then there's that obelisk in Act 2 (i think) that's placed ridiculously close to the salvaging anvil at the blacksmith, I've opened at least 3 rifts by accident instead of clicking the anvil.
I know, rift keystones are incredibly easy to get so it's not a huge waste, but still!