slayer,
If it makes you feel any better, I know first hand from personal experience working with bear biologists from the NJ Division of Fish & Wildlife that cubs of the year CAN in fact survive without their mother. Research in NJ has repeatedly proven that cubs orphaned after August/September of their 1st year have a high rate of survival on their own. Most of these cubs were orphaned due to the sow being killed in vehicular collisions, or being destroyed by Division personnel for being "nuisance" bears. These cubs will often stay together and den together over the winter. Cubs under 8 months old are sent to a wildlife rehabilitator.
That being said, obviously cubs-of-the-year orphaned during the spring bear season by indescriminate "hunters" are doomed to perish themselves. I also don't & won't advocate the killing of a sow w/ cubs regardless of the cub's age, even where legal. IMHO if you're that hard up that you have to shoot a sow with her brood in tow, maybe you should consider a new sport. ..Just my 2 cents worth.