Come on guys, more of a cheap shot in my book. If Justin Bieber came to one of their concerts, liked it and asked to encore with them, I would hope for a grown up, collegial response. They are essentially in the same business. And they'd probably be flattered too.
I would have expected Nikki - whose music with Sixx AM sounds closer to Bieber's than to Mötley's in places btw - to have more style.
Flipping the bird at a teen idol who could be his son, wow, what a culture-defiant, fearless and risque act ...