Dave W. and I flew into Portland OR airport in June last year (from Washington DC via Phoenix AR). On the same 'Tour' of the USA, we also flew into (and out of) New York, JFK, and out of Seattle (Tacoma). Other parts of our journey were undertaken courtesy of AmTrak. Throughout our visit, we wore kilts, Utilikilts or (yes, I HAVE to admit it, because they are so much more comfortable than sitting on masses of pleats for hours on end) purpose made masculine s----s.

Nowhere, that I recall, did we meet with any rudeness or ill-treatment from the security personnel. Some of the procedures perhaps seemed a little unnecessary, but if the traveller approaches the experience with the right attitude and is prepared to co-operate, then all will be well. Yes, wanding became necessary on occasion, but so what?!
As far as footwear was concerned, we were prepared and wore either sandals (without socks, of course!) or slip-on shoes that were easily taken off and replaced. Loose coins, watches, keys, etc. were placed in plastic bags minutes before reaching 'security', thus keeping all the small metallic bits and pieces together, which were easily put into the little dish. The security guys were advised of the large brass/chrome buckles on belts, and of the press-snap fasteners on the Utilikilts before we walked through their arches, which always seemed to be appreciated.

It was not only whilst travelling that we encountered these people; museums, tourist attractions, etc., etc. also had strict security checks in operation, especially in NYC, but that was no problem to either of us.

Maybe our English/British accents helped us!!!