May I ask why you are so upset about the return of metal templates? The airlines have rules about carry-on size. Do you routinely carry on luggage that exceeds the published limits?

I always carry on my luggage, but I make sure my bags are within the limits. I would be fine with metal templates at the airport, because it won't prevent me from carrying on my luggage. In fact it is likely to help me by reducing the chance that I'll have to gate check my bag due to people filling the bins with oversized luggage.