I think wearing veils is offensive, for the most part, for reasons I'll elaborate, but I also think that the right to wear them is fundamental to the values of this nation and must be tolerated absent legitimate health and safety reasons. Normal school activities would fall under the sweep of the general mandate for toleration.
I will briefly outline my personal opposition to veils. In a liberal democracy which thrives on openness and frank exchanges among citizens, veils present an obstacle, and a rejection of the very values just mentioned. An aura of secrecy is created, perhaps compounded by today's concerns about theclandestine planning of harm. In that light, veils are not only strongly symbolic but maybe even instrumental. From a human-respect standpoint, which may be called a feminist standpoint, the use of veils could signal acceptance and perpetuation of a harmful, limited role for women dictated by hoary rules developed in an unenlightened and harmful (to women) age.
But those are my concerns. The basic libertarian stance articulated by Ami -- live and let live -- is however the important "rule for decision" in this instance, which is supported by a host of other fundammental considerations, which I won't elaborate beyond the following notations. "Autonomy" (in tandem with "consensus" and "social cohesion," against which autonomy establishes a dynamic tension) is a prime value in our society, the deft working out of which in the social milieu is the essence of the American promise. Further, a specially-protected subset of autonomy is religious expression, which, on balance, must be favored over the benefits of promoting easier intercourse among citizens.
In the end, the use of veils, presuming a normal course of acculturation for all concerned, presents only an obstacle to human interaction, a prime concern, but certainly not its elimination. In any case, as we're structured and as the problem is being defined here, the accomodations to be expected from either standpoint, and the salutary debates they create, are indeed, in a sense, the essence of America.