P.S. Adding screenshot showing that opentable is blocked from accessing my location. Thanks for any help!

So you're saying that you are in New York or somewhere other than DC suburbs, your VPN exit node is in the DC suburbs, and OpenTable detects that you're in the DC suburbs, overriding your home location setting in OpenTable. Is that correct?

Almost certainly OpenTable guesses your location based on the exit node's IP address. You can't prevent sites from using your IP address to detect location because you can't connect to sites without giving them an IP address.

You might be able to tell OpenTable you never want localized results.

If not, you could bookmark a page on OpenTable set to the city you usually want to search in instead of going to their home page.

P.S. Just to be clear: the location permission in Firefox refers to precise physical location based on GPS, or nearby wi-fi hotspots or cell towers. It does not refer to the IP address you provide to websites to receive responses.

Thank you. Yes. Your summary of the issue is correct.

This obviously isn't a full solution to the problem but does help me understand the issue and provides a possible workaround. I appreciate that a lot.

I've also asked this of OpenTable, especially the bit about my default city being ignored. I'll see if they ever even acknowledge the question. They didn't last time I brought up an issue. Humorously, I got an automated response asking me to review their customer support. It was the only response I got.

How VPN sets and puts your location that is up to them and how they implement their VPN control. Also how the sites you use to hide your IP address isn't something FF can stop if they choose to show your IP address. Put this way VPN isn't a block but it can still show where your from to the other site so your not truly hidden.