This is what the ‘repeater’ does, otherwise the emergency services would think your location is the tunnel entrance, and not some point inside the tunnel. Which would defeat the entire purpose of having these.Very interesting. Especially considering the only way to do this is to spoof GNSS. There's no such thing as a GNSS repeater as the very nature of repeating a GNSS signal looks like a multipath error to the receiver - unless the signal is modified to introduce calculated TOA offsets, thus spoofing the system.
This is also why only authorised agencies with appropriately trained and accredited installers will be able to source and configure these devices. The scope for misuse by unauthorised people is considerable.