Two factor authenticating Not an impossible thing to implement , probably. Could be a thing that you could additionally enable. Would greatly increase the security of accounts.
Is it impossible to compress? Well of course not, but its a lot lot harder than just keylogging/guessing the password and such.
It could also lead to people enabling it and then losing their device, thus losing access to their account if they dont have restoration codes written on something somewhere. Also just not having the device with you but wanting to play HnH might happen.
Probably not really needed on HnH as I assume that compressed accounts on HnH are quite uncommon, and there are some disadvantages such as the ones listed above. But I think that it is a thing worth a thought. With security its too late to act when something horrible has already happent.