It can, but many times won't.
Here's a quote from Ed Lester- "Yes, opening the hatch can damage woofers.
Depends on your enclosure and car, but the enclosure and car work together, and when you change the airspace on one of those, you totally change how it is tuned and plays.
Most of the time, opening a hatch or trunk releases any possibly back pressure on the woofer cone that would normally help control woofer excursion.
Box tuning gets raised, and if you play a low note at any decently high power setting, it can damage the woofers.
Why do you think it sounds different when you open the hatch?"
http://www.stevemeadedesigns.com/board/topic/107538-why-did-it-blow/page__p__1497512__fromsearch__1#entry1497512
Unloading.