Not flaming you, discussion like this is what makes the DIS great, but I have to agree with the others here. They specifically mention to open ALL zippers and pockets when you approach the guard and that means all, not just some. Whenever I bring a zippered wallet or card case, you bet that it is unzipped and opened for them to see. I don't expect them to dismiss opening a wallet or card case because it's a wallet/looks like a wallet, anything could be in there. They don't want my money, ID, or cards, they just want to do their job and have us both be on our way as fast and efficiently as possible. I don't find them looking through anything I've brought to be any sort of big deal. I agreed to let them search the property I have on me when I stepped into the line, and I know that rule ahead of time so I should either not be shocked that they open/see something in my bag or else I shouldn't take it with me if I would be upset at someone else handling or viewing it.
I wouldn't ever expect them to ask for your permission to unzip anything they find in your bag because you gave them that permission when you got in line for the bag check. As others have said, if they stopped to ask everyone's permission as a courtesy - after you had already basically granted them your permission by getting in line - that would cause unnecessary delays and I'm sure other issues would end up arising.
If you dislike the idea of someone looking in your wallet (which I definitely do understand), maybe a card holder would work for you? The ones I have store 4ish cards on the outside and have a teeny tiny slip pocket in the center that holds a bit of folded cash or another card. Nothing for anyone to unzip or rifle through, as you can just glance at the sides and from a practicality standpoint, very lightweight and functional! When I use my card case at Disney, they flip it from side to side and sometimes don't even notice the center pocket, I've ended up showing them that myself! That way no one is flipping through anything wallet-wise.