It's incredibly brittle. The more frequented a network is the shorter the DHCP leases will be, I've seen public hotspots with 10 minutes of lease time.
That doesn't mean the dhcp reuse the ip if it sees it used. Some old clients do not behave correctly and I believe DHCP servers take that into account.
“Fairly easy” for those of us with a technical background. I'm not volunteering to explain that to the CEO when he hears about this and asks how he can access internal company resources safely while mobile!