Earlier quoted context omitted.
Probably why they pulled out. The show is a bit misleading. You can only go by what the people are saying. For instance, I'm sure at some point the dragon asked "are there any products like this cheaper on the market that do the same thing", at which point you can only believe their answer there and then. I'm not surprised that he pulled out. Just wish my dad did the same.
One of the dragons (Duncan, I think) pointed out how old this fob technology was. This triggered what appeared to be the turning point in the pitch where Deborah(?) realized they weren't buying into the physical hardware but the software behind the company. Sarah Willingham pointed out quite early on how useless it was "the instructions say 'make sure the phone is not muted'? What use is this if I've lost it?". Googl…
(I applied to present on Dragons Den for a robotics project I worked on as an extracurricular at uni - I pulled out when my research supervisor advised that we'd have no chance of having a demo in time)
I understand the Dragons are briefed on the pitches beforehand, and I wouldn't be surprised if they sent their own legal team on the projects - who would dutifully tell them what questions they should ask to the 'contestants' on the show.
...not to say they couldn't possibly have thought of a question like that on-the-spot, on the contrary; but given how fake reality TV is in general (and the BBC is no exception) I'm not betting that what we see on screen is exactly, and only, what happens.