Guess what? I was "definitively proven" when I got the first fresh fansubbed release of げんしけん and started watching without even googling out what it was. Sure: it was one of those rare moments in life that you start watching something without even remotely realizing what it is. The first げんしけん episode started with a... somewhat blurry opening of くじびきアンバランス and -maybe you won't believe me- I did say "duh, another school-fight-magic-ロマン series? nice opening theme, worth watching".
You should have seen my face thereinafter. I was simply stunned. ささはらくん entering げんしけん was an opening even better than GitS:Innocence Making of a cyborg.
And some time later, something even more ｓｔｕｎｎｉｎｇ happened｡｡｡