Depending on your threat model, this may be borderline OK, or may be insanely high risk. We've seen driver exploits in the recent past:
http://nvidia.custhelp.com/app/answers/detail/a_id/3140/~/se....
that can vector through the GPU to gain access to arbitrary host memory (aka, you're in deep trouble). The only "right" way to give access to your GPUs requires IOMMU support and running in a true guest VM, which Nvidia's consumer cards and drivers are explicitly prevented from doing (because they'd like you to buy the Tesla versions, thanks).
This may be a totally acceptable risk on an isolated mining rig, but people should be aware of the heightened risks they're exposing themselves to. Breaking your machine is well within the capabilities of state-sponsored actors on this one, and from time to time (just after vulnerabilities get announced), could be decently within advanced-script-kiddie zone.
Thank you for pointing this out.
Also, one of my friends working on this project is a sophomore in the CS dept at CMU, and given your interest in distributed systems & DL, would it be possible to meet up for a couple of minutes and discuss security a bit more in depth? (if yes, I'll shoot you an email)