Hm, I had the same problem now with several mice. I mean scroll wheel = button seems to be pretty standard this days. And I even fight with the same trouble often enough - accidentally pasting stuff into code without noticing. The only problem with disabling the middle-mouse button for me would be that it's the only way to copy-paste from consoles. Which again already doesn't work when trying to paste into the browser so I already must often do something like - copy with middle mouse button from console to some texteditor, copy it there into that other buffer - and then paste in the browser. Not to mention the regular guessing about which application will work with middle mouse button and which won't and which won't work with the other copy-paste. It's rather a mess right now in X.
Most mice I've used require a substantial amount of pressure on the scroll wheel in order to depress it and count as a click. Additionally, there's a noticeable (both tactile and audible) response when a click on the scroll wheel happens.
If the mice you're trying don't have those, and it's very easy for you to inadvertently press the middle button, then that does seem like a pretty major design flaw. If you're always buying mice from the same manufacturer, perhaps investigating a different brand is in order?
If getting better-designed hardware isn't an option, then I guess the alternatives would be improving your finger control so that you don't accidentally click the button while scrolling, or disabling it in software so that it doesn't matter. Honestly though disabling it and missing out on that functionality entirely seems like the worst of those choices.
I also loved the feature once madly, just lost that love at some point. Maybe I'm just more used to pressing middle-mouse all the time for other reasons as Blender uses it for navigation (as well as other 3D tools I'm working with).
