ApologiesI'm not sure what you're referring to by practically, but someone on twitter recently complained that his elderly dad found he was banned from buying tickets when he came back after the takeover because he'd cancelled his direct debit before the minimum term of his membership years earlier.
In any case, the point really was that a membership is a commitment. Even if there is a way to get around the 12-month minimum term in practice, 99% of people won't try that. They'll just not take it out in the first place if they're not ready to commit.
I was talking about the period after the first 12 months. I forgot it was different at first.
After first 12 months you can cancel any time you want