At least in my case, for about 4-5 years I used for the most part a 30 litre MEC daybag as my extended weekend warrior pack. I wouldn't say I was ultralight, just decently lightweight. I usually only strapped my blue foam pad on the outside middle. I'd get some strange looks at the "daybag", especially when I was out for 4-5 days which was about the max I did with it.

Now I typically carry a GG virga - what I carry hasn't changed other than the blue pad is on the inside and everyting inside it. - which makes it look decently bigger enough that I don't get many more strange looks.