I have to say, Its a great idea.
But, I only use dungeon to PvP, Without spawning like this, I never find ppl without /tpa.
(If this idea is accepted, Please remove /tpaccept from dungeon)
It's like the wildy, I Joined meep like 3years ago and still have never seen a single soul in wildy without us both heading to a chest, One of us loots then just /warp alpha's it out.