Originally Posted by adobbing

Based on my experience at other Hilton properties, the door would need to have a card reader tied to the same system used by traditional keys and Digital Keys for everything else (room, lifts, etc.) Also, for online check-ins, you would need the digital key pushed to your phone. As a US citizen visiting Europe, I typically have to visit the front desk with an identity document before the digital key will be enabled...likely not an issue for UK residents though.

I suppose they could install (or have installed) an intercom that rings the front desk and they have a capability to remotely unlock the door.