When browsing the main listings on my phone, it appears that when I try and hit "Next" to go to the next page, the phone sometimes thinks I was trying to click "Expire" on the most bottom deal. The positioning of both are very close.
Sure, I should be more careful (and I am now that I am aware of it!) and that maybe I should use the mobile version of the site (but I like the full version!), but there is the possibility that this happens to other users and deals get expired early without anyone ever noticing the misclick.
Just thought I might point this out. Not too sure of a perfect solution, more something to keep an eye on.