I disagree with the "packing the lane" idea, in the terms that I think a lot of people like to picture it. Like mike said, I doubt there all just stuffed in there waiting for the 3 second call to come.
I tend to think of it in terms of super aggressive defending of the low post, all out hard going. Which I also think is why when you get burned by 3's when playing -5, you really, really get smoked. Over-defending, if you will. Most times in my experience, it's been very good passing teams that have scorched me from 3. I also think the reverse holds true for +5, with the possible exception that the passing required is a lot less than I would expect.
For what it's worth, I usually do not make a distinction of what the defense played actually is, except to exploit whatever particular weaknesses come inherent with said defensive set. For instance, knowing FCP to foul more than other D's, I like to run them uptempo to greatly increase the fouls on them, provided I have either a very fast team, or a fast and somewhat athletic team. Usually pointless to uptempo FCP if you have neither.