Eh, it's possible. Like I said, HSV doesn't have them and likely won't, so I don't know very much about them and how they're supposed to be getting used.

If I hear anything though, I'll try to let you know, obviously within boundaries of what SSI would allow me to say.

Off-hand, and with even more speculation incoming, even if it was used in the public area outside the checkpoint, from what little I do know about the devices it wouldn't be anything more or less different than a drug-sniffing dog walking by you and hitting on a bag of weed in your pocket or something while doing one of their random sweeps through the airport. You never gave consent for the search, per se, but since it's not a physically intrusive or delaying search in the first place, and that it happens to nearly everyone that just happens to come in the general vicinity of the dog (or, more accurately, that the dog happens to come into their general vicinity) then it doesn't matter.

I don't know specifically, but I don't think that the Fido device has to have close proximity (as in, within inches) to detect something - unlike, say, a hand-held metal detector.

Hence: The TSO-in-question might have been checking the whole entire area around him, while standing in that one spot and not necessarily near anyone in particular.

The better question would be - what happens next if the Fido device had picked up a whiff of explosives on such a general-area search? Alternatively, he could've just been showing the two TSOs how the thing works.

Ultimately, I'll have to try to find out more about them.

EDIT: Just looked up some of the information about it. I was thinking of a different piece of technology. It may be another variant of the Fido device, which, as it stands, is used for detecting liquid explosives inside of bottles and not just general explosives. I'll have to do some more research when I have time to try to suss out what exactly it may have been.