Instead of arguing with me, why don't you ask the next a/c guy you meet, whether or not they're familiar with this?
What you think about the properties of duct tape is irrelevant. It's been used for decades for the exact purpose I described, which is how and why it got its name.
I don’t mean to be argumentative but my Father worked in heating and air conditioning at Eglin AFB for just about 40 years.
A lot of that time was spent at the climatic laboratory.
He installed the AC/Heating in our house when I was younger. He used no tape at all. We (my brothers and I) helped him install the duct work. He is the one who told me not to use duck tape on anything which was going to be subjected to any stress, wear or the elements and certainly not for long term use.