I can see a problem if these are publicly schooled children.
But I could see that for school children it could be a different look.
Only thing I am saying is if they want to teach kids about relegions then show them all of them (while the major ones). Don't just do Islam. That way its fair and not one group is being favored and I couldn't really consider it indoctrination if you are giving multiple view points.
All though I do know in the US relegion and state are touchy issues, especially if its Christianity that is the relegion. Seems people get more pissed at christianity when it crosses in schools or the public than other relegions.