What I'm less on the same page with most of what I've read here is "loopholes" always being a bad thing. IIRC Tom was pretty good at exploiting any loophole that he didn't deem to be unethical. For example:
At one point in time, steroids were not illegal, and Nebraska used the hell out of them.
Partial Qualifiers
Fumblerooski (and other trick plays some might consider cheating)
My point is that I think that Coaches who try to use every possible way to make their team competitive, while not technically breaking any rules are smart, not unethical. Sure, there are unethical loopholes, like over-signing, but I think that TO and HCMR are similar in terms of "creative" use of resources. I think HCMR and his staff has done that with recruiting, to some extent.