The sun is lower on the horizon in winter and higher in summer. Planting deciduous trees to shelter a southern exposure in summer is a time-honored way of managing sun exposure and solar heat gain. So, if you want to recommend against it you’re certainly free to do so, but it goes against a lot of accumulated experience and wisdom.
Just because a lot of people say something does not make it right. There have been a number of studies on this. http://carmelacanzonieri.com/library/6123/Heisler-IndividualTreesSolarRadiationSmallBuildings.pdf
This one for examples shows 40% shading by a maple in winter. That is VERY bad. My point is not to use trees, but to do so with awareness a good sense. Just willy nilly, “Oh trees lose their leaves in winter and shade in summer” so it make good sense to plant “dense rows” of them could lead to efficiency disaster. A dense row of maples could block 70% of your winter sun.
Two of the three passive solar homes I built used existing site trees for shade. The best was three trees only on the south side, close to the house. The lower 30-40 feet of these trees had no branches whatsoever. Even then however, it was noticeable when the shadow of the trunk rolled across, and it increases the risk of property damage.
So I wasn’t, and am not, trying to slam your recommendation, but rather to refine it with extra knowledge so that someone will not misapply it to their own demise. :-)