Venting into the house makes the house stink, when you go in and out of the house you are venting that smell at street level. Venting into the loft makes the smell travel further.
The real tell tail is when it snows. I have less snow on my roof than my neighbors, so for 2 days a year that's an issue. Gonna insulate the roof with spray foam this summer.
The filth would need to suspect you have a big old operation going to look for way TBH. Domestic property grows that they are on the look out for are most likely whole house set ups. I would imagine a quick look at your home from the trained eye would show you are actually living in it, that would lead them to think it's a personal grow and not really worth wasting their over stretched resources on, depending on where you live of course.
