I had a planet bike trunk box on a beater bike I use around the junk yard. I used it for tools and whatnot. A dropped car ended its life unfortunately. Main reason I don't use one on the road is that they are rather ugly imo. It does block the reflector on the seat post, but some reflective tape takes care of that. I don't believe a wedge pack would work with one of these either, but I prefer handle bar bags anyway. That being said, these would be very handy for locking up helmet, lunch, gloves, etc. Nothing is truly thief proof, but these would keep random people from trifling through your things.