very briefly. I am a cold sleeper, so I use a zipperless bag even on warm nights. I tried using the Trails bag, but I would always feel chilly. I felt even the slightest of drafts, as there is no loft, the Driclime just wasn't warm enough for me. I used it as a blanket at home, as it unzips fully, but then felt like a gear wierdo and sold it.
I too agree that as an overbag, things would be a bit tight, however, I never tried it as a liner.