In our lineage, priests
a) wear simple blue, black or gray clothing, in that order of preferenceBeyond that, there is an expectation of living a "pared-down" life, though that will, of course, be subject to circumstances. In any event, opulence and luxury, adornment and focus on fashion, are to be avoided.
b) keep the hair short for women and very short (buzzed though not shaved) for men
c) wear shirts that have no collars or only a band collar
d) avoid animal products in clothing as practicable and
e) if men, keep the face clean-shaven.
By and large, it's pretty easy not to stand out in a crowd this way. A navy sweatshirt with blue jeans isn't distinctively "Buddhist priest" wear. But with no collared shirts, neckties are out. With the color restriction, most sports team insignia apparel is out. OK, so there are a few situations where one doesn't blend so easily in, but this is hardly oppressive.
And yet there is grumbling even about something as simple as this!
It is one of the marks of Baby Boomer thinking that requirements are by their very nature pernicious. The Boomers gave birth to "Generation Optional:" everyone gets choices, because choices are by their very nature empowering.
Last I heard, Zen was a practice of avoiding picking and choosing, a practice of renouncing the multiplication of choices in favor of a mindful, straightforward life, characterized by equanimity. I'm not there yet, but I have to say I find that I'm much freer to attend to better things when I'm not worried about updating my phone or mixing up the wardrobe or the rest. While not quite a No Comprendo Zone issue, I do wonder why there's so much resistance among Buddhist ordaineds to letting such stuff go. What is that?
I do not believe one can be "nonattached" in mind only. Nonattachment is demonstrated in truck with everyday life. Maybe it's what koan training has done to me, but I can't shake the view that commitment and insight have to be demonstrated.