I'm awaiting a Nano I picked up from Apple's refurb section (my shuffle has played its last tune, and the deal was too good to pass up) and I plan to use it with the Nike sensor kit. However I really loved Apple's armband for my shuffle, and when I went to look at Apple's for the Nano I realized the bottom of the armband is closed up - no room for the Nike sensor! Has anyone had any success cutting a slit at the bottom of the armband for the sensor? Is the armband snug (I've seen people wearing it with the nano facing upside down - is this safe?), or will the nano bounce up and down against this slit a lot, widening and eventually slipping through it?