At minimum scrub it...constant stream of hot air coming out of anything, sewer pipe or not, is easily seen on flir like a flare gun regardless of smell risk.I've read many busts of people doing the same thing.
No, that's why you want to vent on the side of your place and not out of your roof like a flare gun. Just make sure the vent going out is not letting hot air escape into the wall and spread but run directly into an ac unit.
The best way to vent outside (although I would never grow in a house again where I had to do this) of your place is venting right into the air conditioner unit outside. This is because the the hot air coming from the air conditioner blowing straight up is well, already hot air
Awhile ago at an old spot I had 4 instances of cop helicopters shining spotlights directly in my back yard and cops with flashlights looking for suspects (bad neighborhood). Not once did I get raided and I was venting 3k watts right into the air conditioner unit outside from the wall. If this is not an option vent into the middle of your house through the attic? I don't know sewer pipe venting is about as safe as venting through the chimney...easiest thing to see from a heli. If they can zoom in on where someones hand has been 5 seconds ago from hundreds of feet away and still see the heat print they can surely see a shit load of hot air being pumped straight up. And yes I have seen a video where they did this and it absolutely blew me away.
If there was any chance they could see it they had plenty of time on multiple occasions. Scared the shit out of me!
If you have to go through the roof I wouldn't stay where you are at any longer than a year. Hope you can figure something safe out. Venting outside is scary to me I always find houses that you can vent from one room into another as a lung room or vent from flower room to center of house through the attic.
