[T.G]

You can, although depending on how they are constructed and how much of the cap you cut away, some pre-cut cigars can unravel after sitting in the humidor for long periods of time. You also have to be a bit more careful handling them since they won't have much holding the head together anymore.

And, lastly, if you gift a cigar, some people don't care for being given one that is pre-cut. As it can be viewed as "tacky".