It's funny people comment so much on this issue, and calls photographers perverts and what not (who in fact are hired to take these pictures). Reina herself have commented on the "showing a little extra" thing (which is done on purpose), that it's basically fanservice, and she has nothing against it, and it's ok to look.
Yea as Krusha said Reina doesn't mind it at all because they're wearing "Safety Pants" as they call it hehe ^_^ like the interview with the High - King with Mari as the host and two other guys hehe ^^
@ ilove-momosu, it IS Cinderella Complex. All of the girls participate in the dance but not all of them sing, I'm pretty sure. That's the only song where Reina does this move, but I'm unsure about the new choreography for the other songs that they implemented.