I think the original post was a joke, but the different views have been interesting. First of all, no matter what you wear, if you're traveling with 32-38 other people you are not going to blend in. Secondly, I've traveled independently many times, wearing black, good leather shoes, coat, pants, etc. and have always been recognized as American even before I spoke. When I asked the clerk in the Bon Marche in Paris how she knew, she said I knew looking at you that you were either American or British. On another trip, I took the train from Rome to Chiusi sitting in the first class compartment with three Italian women wearing blue jeans and white shoes. I was in my usual travel black.
The suggestion for Merrill, Eccos, etc is good providing you wear a size under 11. I've developed tendonitis and need orthotics, which means size 11-1/2 or 12, which are virtually impossible to find other than in a sneaker type shoe. I wear size 11 Ecco sandals but cannot wear Ecco closed shoes because I'd need a half size larger and there aren't any!
So, it is not a matter of preference for me any longer. Cole Haan used to make 12s but stopped a couple of years ago. I was in a Merrill shoe store yesterday and there were no women's shoes over size 11. If I have to wear white shoes, then that's what I'll wear and I don't think I'll be the only tourist in Europe or anywhere else in white shoes.