Moving couch--concern with LP monitor??

Hi everyone,
We have a 3670 and are workcamping for the summer. We are thinking about moving couch and recliners around, putting the couch up against the back wall. That is where our Safety Alert LP monitor is---any concerns about putting the couch up against it? If we ever would have an LP leak would it flow under the couch and still warn us (I think LP is heavier than air)?
In Prosser, WA for the summer
al

I would think that since the couch is tall than the rear window shades, you would still have a few inches of an air gap behind the couch.