That is true, the location proof is only for the hardware whose IP is used for submitting the vote request. However if remote desktop provider / cloud provider / VPN / Tor IPs are already blocked by the voting platform. Then it would require significant effort to acquire hardware in the target geographic region and equip it with a residential IP. Generally the whole setup only makes sense if IP's (or IP ranges) can only vote once per poll. Then large scale manipulations should become impractical.