I was pondering what the effects of y2k might be on frequent flyer miles and programs and wondering how much of a risk there is that they will be worthless. What do you all think? What steps (if any) can be taken to safeguard?

I am not worried at all. Even without MMbug - I never rely on any ff-computer-account. I keep the paper-statements and save also online-account-statements from time to time.

There is as close to zero risk of this as is humanly possible. The databases that store your account and flight data won't get lost or corrupted. The only risk, and this only if the airlines don't fix things in time, is that some old programs may not interpret the data properly and may give you an incorrect balance. Even that risk is miniscule because FF programs have had to deal with post-2000 dates, in the context of mileage and award expiration, for a long time. The likelihood of actually losing miles, or not getting credit for early-2000 flights, is orders of magnitude smaller than the likelihood of being struck by a comet at exactly high noon. Compared to the other risks of air travel, such as slipping on a wet jetway and breaking your leg, I wouldn't worry about this one.

(I spent several years as an information systems consultant getting paid by some pretty big outfits to advise them on this sort of thing.)