I've tried it and it didn't work, a can must be in place BUT no where is it written that the can must have a front. There are a couple of holes drilled in the can and a set of optics are lined up with those holes in order to read can being full. There are also a couple of plastic flags in the chassis that when the can is installed are pushed up and block a couple of sets of optics in the bill transport. ( pull the can out and you can see them very top rear of chassis )
It's been a few years but I seem to remember when I cut the can front off I had to leave the large spring and the plate that holds the bills inside the can. I cut the whole front off but if you think about it, only the top 1/3 would need to be removed. I think I also removed the cash can door. If you do this watch for sharp edges