kenny1982, for the sake of immigration and your future relationship with your family, perhaps you should at least inform them of your decision to get married and seek their approval, even if they don't approve. At least, then you can answer the IO's question about parents' approval (which we were also asked, it's a pretty common question) with that you sought their approval but they just couldn't accept the fact that your spouse is a different nationality, and it's not something you could do anything about to get their approval. But, you know your parents best so handle the situation as you wish.
Is it absolutely required to have the family's knowledge of your wedding to be approved for permanent residency? Of course not. It's just one of the things they look for because a typical married couple would get their families involved. However, the IO will look at your evidence in its entirety. Having the families involved in some form, and being able to claim to know each other's families just improves your chances for approval and reduces the risk of being denied.
To give you an example, they also look for the married couple living together, which was not the case for my wife and I. Instead of a typical 15-20 minute interview, we had a 45 minute interview and our living situation and plans to live together was the central part of our interview. We were ultimately approved, but it was certainly an uphill battle, missing one of the elements they look for in every marriage.