Would you buy this modification from Canon for $100 USD?
No mention as to the cost of shipping.
From Canon's web site....
This modification is available, for a fee, to owners of these cameras who would prefer a Mode Dial which locks in place and can’t be accidentally moved during normal camera operation.
For USA residents, the pricing of the locking mode dial modification service for EOS 5D Mark II and 7D cameras has been set at $100 per camera as of December, 2010. (Pricing and availability subject to change without notice.)
(See site for pics of modified dial.)
Once modified, users must first press and hold down the central lock-release button in order to turn the Mode Dial. The modification is intended to prevent the Mode Dial from accidentally moving, once set to a particular exposure mode by the user.
IMO, I think if there is a design flaw with the dial not staying put, as set, then Canon should do perform this fix at no charge, just like the fixes made available in their firmware design flaws.
The dial changes quite easily on my 7D, only a small amount of tension while turning it. Dial has changed at least three times on me.