The top of the window could eventually be seen by someone standing outside of the plastic cover, but, ceiling height being 2,80m (norm in Portugal), nobody entering, except for a giant, could be spotted.
I think this illustrates it rather well, altho the foliage had grown at this time.
This photograph was taken from outside the patio windows. It is easy to understand what the Mccanns could see. When we were there the foliage must have been fairly recently trimmed as when Madeleine was taken

The building with the picture windows immediately on the other side of the pool is the outside tapas. It is in two adjoining halves as you can see. We sat in the LH half behind the pool so towards the middle of the combined structure. We had a near perfect view of the side (for Faith) of the stairs and of the patio doors. Although some of the view was thru the railings, we could still see the patio doors virtually from top to bottom and from side to side.
The Mccanns sat in the RH half of the structure, somewhere behind the slim tree trunks that you can see. The big table was positioned there. They must have been two or three metres further west than we were, but as you can see, even tho the greenery needed pruning in this photo they still could see quite well. With the greenery pruned right back as it had been on May 3rd they would have had a very good view.
I think you, Anne and Faith, must either have been sitting in the main tapas bar which is further west ... or else the foliage must have been very overgrown. Greenery grows astoundingly quickly in western Portugal. Rain comes in over the Atlantic and it is warm. Nice climate.
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This is a soon-after contemporary photograph of the foliage at the time of the abduction Some may remember Gerry commenting later on the fact that the view had changed because the foliage had grown.
The photo was taken from the "watchers" balcony. Policeman in position. Bushes are cut back. I think somewhere in the files it comments about gardeners in their garden working whilst the Mccanns were there. But not sure. Can anyone remember?

There is another photo somewhere which I cannot find. That shows the bushes even more shorn, especially the round one.
With bushes cut back, there would be a much better view than in the upper picture shown. Yes they could see most of the patio doors and steps up.