Based on your logic the average customer wouldn't try to open the iPhone with or without special tamper-proof screws. Let me tell you the obvious way this WILL hurt the average consumer. When a so called average consumer tries to get their iPhones repaired, the only way they would be able to would be to take it to an Apple authorized repair place. Or maybe a repair place that got extremely expensive fancy tools. This has no benefit for anyone other than Apple's control.
Smart consumers have Apple Care and thus don't have to worry.
Also, let's not act as if the average consumer has to have his/her phone repaired every 5 minutes.
What I see mostly is cracked screens which people have repaired in malls or via mail in places for fixed pricing.
By using those kinds of screws Apple tells everybody that they don't want unauthorized people to repair their products.
Yes, they prefer to fix their products and you can call it control if you like.
There are some butchers out there!
Now, obviously money wins out and most consumers will go wherever it is cheapest.
I have tinkered in my MBPs, and other Apple products I had and I don't think any special screws would have stopped me from getting in there.
Not really a big deal or worth getting upset about.