Dear Matt and Marcella,
It has been about 14 years since BTS (Sky Train) have been in service, originally it was rather a one dimensional service (up and down Sukhumvit and Silom road). Through out the years BTS coverage has grown and is still growing, together with MRT and its expansion, travelling around BKK have never been so easy :)
I think by the time you two are old enough to be let out by yourselves, not a single drop of rain nor a single ray of sunshine will touch the ground :) the sky tracks and sky walkways should by then cover every inch of sky around the center of BKK :)
Not a bad thing really, considering by then the green house effect should be in high gear, sunshine would be the last thing on the list one would want to come in contact with, well, apart from the acid rain that is, haa haa haa.
So the permanent overhead protection would be very welcome in deed :)