MACs are 48 bits, and the unique ID is 24 bits if you preserve your real OUI. This doesnt have anything to do with with an IPv4 address.
Furthermore, "professionals" rarely randomize their IPv4 address; theres almost no value in it. The subset of people with some kind DHCP filtering but no NAC or DHCP enforcement is miniscule.
If a subnet has 254 machines, they are all made by the same vendor, and the last 3 bytes of the mac address are randomized for every one...
There's (254*253)/2 combinations of machines.
Each one has a probability of about 1/16777216 of a collision with true random numbers.
The number of collisions you expect in this scenario is ~0.0038 over the network. With the wacky problems that happen on MAC collision, this is rare but still too common for routine use.
But the chance of any issues, if now and then a few professionals randomize their address, is basically nil.
MACs are 48 bits, and the unique ID is 24 bits if you preserve your real OUI. This doesnt have anything to do with with an IPv4 address.
Furthermore, "professionals" rarely randomize their IPv4 address; theres almost no value in it. The subset of people with some kind DHCP filtering but no NAC or DHCP enforcement is miniscule.