Knowing you could get paid more elsewhere, would you accept the pay cut to prevent layoffs or would you leave?
I'm not ashamed to say that I would probably leave. Loyalty shouldn't be expected on either side, and that's ok.
I agree, it's not reasonable to expect loyalty in either direction. I think the key for employers is to remove as many reasons for leaving as possible; then who cares if employees stay out of loyalty or out of logic, they're still staying.
edit: typo
So the owner asked if we'd all take 20% or so paycuts, with some of the older/better paid staff and the owner himself taking bigger cuts. As the business was otherwise profitable (being in a pretty niche market) we all agreed. Something like 9months later we all got paid back with interest and a bonus.
Smaller scale, and a bit more recently at a different (also small) place, all the non-management staff offerred to forego the (expensive) christmas party so one of the contractors could get paid back pay they were owed due to problems with a difficult client.
It's obviously very situational, but in both cases it felt like the right thing to do and both places were smallish firms where loyalty and morale etc. at the time, were high.