I have no issues with dress codes being enforced. I also don't think there's any reason why dress codes should be lightened up.

My previous place of employment required interfacing with business people; everyone dressed business-like as it's part of the culture. Clients who came in with sandals, shorts and t-shirts could because they were paying us, and they can wear what they like (within reason). UA (and it's employees) is basically a service industry and needs to consider the image the employees projects (on the clock, or taking advantage of a perk). I know the last sentence will get chuckles from bitter/embattled UA flyers but really, they are technically a service based industry

Why some think that they can dress whatever they want baffles me, considering they are taking advantage of a perk under the policy of their employer. The NRSA's should follow the prescribed dress code. It's not an unreasonable dress code either.

As to the OP's posting, if the NRSA was willing to rent, he might as well just gone to one of the stores in the airport and bought a cheap pair of appropriate shoes... at least he'll get something for it, AND fly in business.