prejudice ? yes.
reasonable? probably. i guess i'd want to see the clock but the authorities said, "no danger in the device, but could pass as a fake explosive" the teachers are trained to be cautious about these things. one just can't turn a blind eye to a possible bomb because someone's feelings might get hurt if your wrong. safety >> feelings
...but the 3 day suspension is stupid. the kid made an honest mistake here. yeah maybe the thing looked like a bomb but it doesn't seem intentional in any way. both sides should appologize and then everyone should have a laugh about it. suspending the kid is just not necessary.