Ah, memories... If you have the sort of sleeping bags that are shaped like rectangles (instead of the more wintery mummy bags), and two of the same bag (brand and model), you can unzip each one flat and then zip them both together to make one double-sized sleeping bag. Gives you plausible deniability for packing.
(I think I actually learned this tidbit as part of wilderness first aid training — snuggling is the proper emergency treatment for hypothermia, after all — but the implications were there.)