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Oddly, I could never accustom myself to the touchpad on my Mac laptop.
Nor cold I when I was forced to use my wife's MBP. And she also uses a mouse instead of its pad. But i think the reason(s) may be both the laptops pad being much smaller (and sometimes with a separate 'button') and the locations being different. The laptop pad is usually under my thumb, not my fingers. Plus the Magic Pad is off to the side where the mouse usually is/was. I must admit, however, I still find it difficult to make fine, detailed, pixel-specific selections or movements. I still use the attached Magic Mouse for those tasks; the tiny scroll button no longer works, but it is much easier to position the cursor/pointer precisely.
Not sure what OS you're using, but I doubt it is above 10.6. As far as I know, if you are logged in as the Admin, you won't get any requests for installing anything, anywhere except for OS installed areas/files (Pref Panels, OS Plug-ins, etc.). An "Admin" should be able to install any app in any users account. More recent restrictions apply to the 'signatures' Apple provides to developers and also can be limited to stuff from the App Store.
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Maybe the old brain is becoming a little fuddled.
Nope! I have documented facts that prove there are many youngsters who change behaviors in our software!!! Most of them think it is amusing! I only hope they feel the same in a few dozen year!
Sometimes, they even find a way into our house and move things around! I usually find what I'm looking for, but it's seldom in the place I know I left it! 
10.8 is even worse! In the Security & Privacy Pref Panel, there is a setting that allows downloading from:1. Mac App Store
2. Mac App Store and identified developers
3. Anywhere
The default setting is #1 (I think). If the user attempts to download an app from "anywhere," the OS throws up a dialog that simply says, "The file you are trying to open is corrupted. You should delete it from your Mac." I downloaded a Citrix Web-based conferencing plugin for my wife four times before I realized there was nothing wrong with the file! I simply needed to change the setting in that Pref!!!
I can accept "Big Brother" trying to protect me from myself... a little. But don't give me a bogus dialog that actually lies to me about what the problem is!
I haven't lived this long without being able to face facts!
(Despite the fact that I repeated the same act four times in a row, expecting different results...
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