In the case of pacemakers, I can definitely understand some nervousness in the early days of the technology, considering that microwaves evidently can have a negative effect. So, yeah. But at this point, I think those fears have been disproved when it comes to cell phones - and I doubt this lady had a pacemaker! So I would have needed some lead-up, at least. ;-)

I've been wondering how I would have reacted had she bothered to explain, and I suppose she was right to storm off, because I would just have referred to the airplane mode (which she probably would not have understood) - and of course I had an actual cell phone in my bag.

The waitress said she's a regular (and is always odd). Let's hope she never finds out about the tea house's wifi hotspot. ;-)