Indoor deployment is a common thing snipers do. While they do it, they are expected not to deploy directly in the windows, since that allows for significantly lower profile and less loud sound propagation (though don't know if that's implemented).
The problem is: with weapon stabilization introduced, we still have an issue with a furniture that, as we know, has mysteriously disappeared - and you can't move it even when you have it. Thus a sniper which avoids showing up will be forced to shoot like a drunk man, with his muzzle jumping splendidly.
This wasn't significant before stabilization shipped out, and non stabilized sways were as controllable as stabilized are now. {F26266} {F26267}