Attilio Anthony John Wagstaffe
Same here Sensei as you may probably know from my history page....
If I/we or my old students visited another dojo or organisation, we would always wear white belts, unless instructed by the sensei of that dojo otherwise.... It has the power to stop accidents happening to, as it served as indicator of someone's level and what they were capable of receiving, but as you know that is not always the case......
I adhere to the same practice as well. I also do it at my own dojo when attending classes of martial arts I don't normally train in.