I hear you. The problem with empty threats is that children learn that their parent will never follow through, hence, they learn to believe that there are no consequences for bad behavior. This becomes especially problematic in later years - like the teen years.
My poor son, I have never made a threat that I have not followed through on. He is almost 16 and knows when I get that tone and threaten to pack up every electronic in the house that I will damn well do it. LOL Used that one this weekend to get my overgrown lawn mowed - and used it loudly, in the middle of the front yard, with my neighbor standing right next to us. Yeah, surprised everyone. Lawn got mowed. Teen had an attitude adjustment. The weekend was lovely.
Anyhoo, when I ran across a parent who had a completely different style than mine I tried to, first, parent by example, so that, at least, our children could come together and play without incident. If that didn't work, I simply moved away from the relationship. The offshoot is that I wound up with a good network of moms in elementary school that shared my style and values and our kids remain friends.