Well I think you have destroyed any good points in your argument if you are comparing parents being inside their own shut and/or locked and secure home with their kids and parents being out at dinner 50/100 metres away out of ear and eyeshot of their kids in an alien environment and unattended
There is also the matter that there was avery good reason PDL did not have a *listening service*
Lets be accurate Red. you have seen the GE evidence. K and G were just over 50 metres from the patio doors NOT 100 metres.
I sat at that very Tapas restaurant and I could see virtually the whole of that patio door. Ther mccanns were about 2-3 metres further along (in a westerly direction) and their view would have been nearly as good. This all depends, of course, on when the rapidly growing vegetation had been cut back.
With the heat and rainfall, vegetation grows extemely rapidly in western PT. From contemporaray photographs, it appears that the greenery within their little garden had just been trimmed. My bet is that they could see virtually as much as we could.
As for sound. If Madeleine came out on to the balcony and called, they would have heard her. No doubt about it. Madeleine was a leader, a clever and resourceful little girl, as illustrated in various youtubes ... and in Tapas 7 statements. Not a shrinking violet, she would have made her presence known, had if she were desperate. Little doubt about it.