Uneven front tire wear on C280

My wife is a slow and very "careful" driver, and I noticed that her C280's front tires are nearly bald at the outer shoulders. I don't believe she peels around corners so could this be due to poor alignment and need the camber adjusted? A friend's C280 of similar age had bald inside & outside shoulders, but this could be from underinflation. Whatever the reason, would placing negative camber on C280 improve it's cornering, and how else will that affect the cars handling? Thank again.

Jim