Hot air ventilates very will through the front with my Sony VW60 that I have had the last three years so there is no need - I monitored the temps for about three months and it never was a problem (the house has central air so it never gets hot inside - not sure it would make a difference if it was substantially hotter inside). Originally I was planning to add ventilation holes but never needed them.
I'm not sure how the JVC RS45 ventilates yet but if need be I'll just add some drill holes and paint them black... again being all black they won't be noticeable.
Keep in mind the picture is with a very bright Cannon flash unit with a heavy exposure - it's almost impossible to see unless you know what you're looking for and the lights are up at least a third of the way. The black box + all black room essentially makes the entire enclosure invisible (except from the front of course).