John,
I am planning to make all buildings removable this go round. I fastened a lot of buildings down to the scenery on my last layout, and wished I hadn't, even for just when I wanted to remove them to make changes. It was a mess and some were damaged. So no matter whether the building is in the front, or even a building flat against the backdrop.
Thank you for all the warning tips you give modelers. Sometimes they don't apply in some cases, they are all valuable. And this one is definitely a tip I would advise for everyone too!