Nick from Inside The Vibe took his broken strap to the source!  Once Wii Sports: Tennis caused the strap to snap he emailed Nintendo the following...

The thin string that connects the wrist strap to the Wii remote snapped while playing a game last night and went flying across the room. The remote still works - very happy the product is so sturdy. The strap however is not. Do you replace these when they break? I played the system a total of 2 hours before it broke. I have read a lot of reports like this on the web including IGN.com and Engadget.com. Maybe you should make that thin string a little tougher - or a lot tougher actually.

And Nintendo support replied with:

Hi Nick,

Thank you for your e-mail. I was sorry to hear about what happened. I’ll be sure to forward your report to the appropriate department for further review.

Also, since you’re a My Nintendo member, I have a replacement wrist strap on the way out to you by UPS. You should be receiving it within the next 4-10 days.

Sincerely,

Nintendo of America Inc.

Look at that!  That's how customer service is supposed to work!  If you have a broken strap of your own be sure to submit your story with pictures to our email address. Then contact Nintendo!