Interestingly (or not), I have had some discussions related to IP address and its uses in attribution and deduping. If someone is using a VPN, IP Address will not work. You have no idea in the household who is seeing ads or purchasing, could be a parent or a child. You can have a child exposed to an ad and the parent buy. Now, all of this may be small enough that you can say “eff it, close enough for gov’t work!” and use it. Just know that it is inaccurate!