I didn't have them on my shee but I did have one wiggle off my street bike. To make sure it don't happen again I put a small bit of silicone around it put in on and let dry overnight. Haven't had one come off since.
It's not the same as in the air box. The airbox is mounted to frame don't move much, the K&N's clamped to the carbs wiggle, bounce, vibrate a hell of alot more.