This gave me a good chuckle! I encountered the same thing. I think it has to do with the feet swelling after wearing it awhile. I don't think it's a good idea to try and wear it through security. Too much hassle and I don't want to be the person holding up line. No help, just some commiseration.
Whenever I talked about this with my friends that had helped me to pull the boots off, we had a good laugh! LOL