From our perspective: yes, we don't feel comfortable letting untrusted users run side by side without a sandbox.

In this context though of GPU compute, you are just talking sporadically to a PCIe attached device directly. There isn't any virtualization or sharing of the device. And yes, I assumed that the complaint would be performance, but especially with just a pass through GPU, it's going to be honestly funny to find the right "oh wow this is 20% slower because virtualization specifically".