Ah. I'm not that swayed by star power myself, but I've had dinner with Takakashi (never get her name right) in 2009 so my perspective is skewered. It makes for a fun story in its own right though. (THAT was a lot of accidents rolled up together to take me along for the ride.)
Does sound like fun, although I wonder how much you could get if you tried to scalp the ticket. I could imagine the asking price to be in the hundred of thousands of yen. It might explain why a lot of people were reluctant to help with the request, because they were probably very focused on trying to get the tickets.
... Although doing the math, if you tripled the amount (Namely you dropped 150000 yen into green tea) assuming a 0.1% odds rate, you're only a 12% chance of scoring a win. Or basically if you bought 108*20 of them... or just over 2180 bottles.
Yeah, that might be JUST a bit overkill, cause I suspect that might be pushing the best before dates on the tea, assuming you went through 3 a day.

The sad part is I suspect Kirin figured out the math as quickly as I did, and figured there'd be people who are crazy enough to try, which means they're going to be making sales fast.
... I'm ALMOST tempted to ask if I can ship the bottles back for gimmick reasons, but I'm terrible with keeping empty bottles around. I'd just lose it on a train, or accidentally throw it out or something. That and surprisingly, I'm idol agnostic, and I like them as a group than having a favourite.
It's nice they did put in the effort to do all the branding though. You should take pictures.
If anyone ELSE wants to pay a shipping cost for an empty bottle, you're free to ship them off as some sort of quirky collector's item, I guess. Feel free to offer any you don't want to keep to people on the forum or something. I'm sure someone'd appreciate the cute stuff.
Ah, but it gets better! The concert prize is super-exclusive and you can't simply buy tickets to this particular show. It's being held at Shimokitazawa Garden, which is a small SMALL venue that I've actually been to before to see Kanon Wakeshima. The 450 winners will be the entirety of the audience, and Garden is going to be jammed like a rush hour train with that many people in it. But the benefit is that you'll get to see the seiyuu up-close and personal, and look them in the eyes during the show. Normally iM@S shows are only held at 8,000+ person arenas (Makuhari, Saitama, etc), so this will be a very different experience for the super fans who win.
My family opened two of the teas to have with dinner. Amusingly, there's a hidden manga drawing of the bottle's character on the inside of the label for each one.
Takane says: "After you eat ramen, follow it up with some Namacha. Huhu!"
(Kirin Namacha is the kind of tea the girls are on)