Yes, Nintendo has promised to replace your Wii wrist strap if you accidentally break it while bowling or perhaps putting in a particuarly vicious cross-court volley. Users can ring Nintendo's national customer service helpline, or send their frayed straps back to the company for a replacement. If you have found yourself the victim of a wrist strap malfunction, you can also fill out the online request form. There's even a dedicated email address - wiiwriststrap@codestorm.co.uk - where perhaps injured and incapacitated gamers can reach experts in the event of an emmergency.
If you haven't yet succumbed to a movement sensor related calamity, please - for the sake of yourself and those within striking distance - read this safety information. Don't let the next black eye be your wife's.