As someone who lives somewhere that just got up to 120° f hot metal is no joke. We had a ton of people hospitalized a few years back because they went to open gates to their homes and weren't expecting scolding hot metal when it was already like 11pm.
I'm not going to hate this because it's a idea that doesn't work, I'm going to hate it because it's just another method to harm people who want to come to the land of the free. On top of it border states like to charge people for leaving out water so just anything they can possibly do to be vindictive and hateful I guess.