This topic has been talked about before and I feel that there will come a time(in the very near future) where MISB only will matter in case of smaller completely sealed boxes like Battle Packs. With the rise in popularity of LEGO sets and their known high values, there will be criminals and con men/women looking to skim parts and minifigures out of the easily opened larger sets. Until LEGO changes box styles and security, a simple hair dryer can remove a seal.
I am coining these phrases now...
VIB...Verified In Box VIBN...Verified In Box(NEW) VIBU....Verified In Box(USED)
Unfortunately, this is where the world is heading. Everything has to be verified. Soon, the most important information will be how many sealed bags a set has so it can be checked before and after a sale.