One thing did (https://www.kickstarter.com/projects/800343142/tylt-vu-pulse...), and unfortunately Pebble just kind of screwed them over. I can't imagine there's any malice involved; integrating HR was an obvious step forward for the product. Backers got an update today advising us that Pebble and Tylt have collaborated such that the Pulse will be able to feed HR data to Pebble Health, so it looks like Pebble have probably been good to deal with.

Still, I imagine it leaves a sour taste in the mouth of anyone else looking at making "Smart Straps".