We just keep our fun stuff in KEYED cupboards, and hide the keys up VERY high (DD2 knows how to use keys - DD1 needs help with keys). However ...

Just keep the magnetic openers out of sight
That is hard ... the little buggers are surprisingly resourceful. We have a mantelpiece in our kitchen that we usually keep all the 'good stuff' on (crackers, biscuits, chocolate, pegs) and DD2 has just worked out how to get up there. It is around 5' off the ground. I was very impressed, DD1 (whose crackers got eaten) was not so impressed.

We have our chemicals up on a shelf that is about 8' off the ground and the knives and sharp utensils on a shelf 6' off the ground and so far those two are safe. I never had these issues with the first child. The two of them are amazingly different.