^haha cool, she must've been like 11/12 years old in those pics
That was from Ikuze! Kaito Shoujo event at Nagoya last Sat (5/22), where Tsukina made an appearance as guest performer (so she's 14 in the pic). She's in red because apparently she appears when Reni
out with a headbutt. All 3 guests (other guests are Sakamoto Haruna, Kojima Honoka [the two next to Kanako in the group pic, left and right respectively] from Stardust) also took part in the handshaking...
(also apparently the girls started dancing along to Onnaji Kimochi [TGS!!!] as it came on in the background during the handshake)
she might return to the group ???
Unlikely, though it'll be interesting to see what Stardust has in store for her/us (she's back with Stardust S3, it was announced at the event. Can't find her talent page yet though).