I did something like this some 22 years ago or so. I can’t remember the exact reason why but essentially DHCP was not reliable enough or it caused some issue with the proprietary network hardware my company built and sold. So I built a little “kiosk” (old laptop with an HTML interface to an database) that would give you an IP and a “return by” timer of 12 hours. Before displaying it would ping to make sure the IP wasn’t active. Looking at this post I know realize that I could have just bought a pack of clothes pins and saved myself some trouble.