Basically this is a failing on Microsoft's part.
Bingo, if this is ever implemented, then there would be a mass-outcry no doubt that its so inconvenient for them.
Everyone wants everything in this world, but the question is: Can we trust them with it all?
You now point I hope...
you should do this regardless of any security. I ALWAYS check programs (if program is small enough I even scan the code) before running it, thats what responsible network administrators do. If you are not checking programs out, then I would not be surprised if you were or are attacked.
It is not impossible, in fact it is very possible.Microsoft would have to create a flag so that programmers can set it to tell the system that it is a security related program and thus should be allowed to execute under the admin account.
Once they do that, the game's over, because the malware programmers would all set that flag, run as admin and go right around any anit-virus software you might think you were running to protect your computer. I'm a Linux user and advocate, and I wouldn't want to see that happen.
Please read above mentioned points, that topic has already been covered.
To save time ill summarize. Malware authors are going to set that. Its expected, and if an admin executes the bad program without checking it out. You now point I hope...
Ya'll hear about the geometer who went to the beach to catch some rays and became a tangent ?