Proof that you actually CAN quit apps on Mac OS X Lion, just for muad_dib on Reddit, since he has no idea.

proc_quit_proof.txt

Current Config (for accuracy, of course):
27" iMac, Late 2009
Processor  2.8 GHz Intel Core i7
Memory  16 GB 1067 MHz DDR3
Graphics  ATI Radeon HD 4850 512 MB
Serial Number  REDACTED
Software  Mac OS X Lion 10.7 (11A511)

Experiment:
I have an auto-login app called "ScanSnap Manager.app" running. I can verify by running:

ps -eaf | grep 'ScanSnap'

Output:

501   977   211   0  8:57AM ??         0:01.58 /Applications/ScanSnap/ScanSnap Manager.app/Contents/MacOS/ScanSnap Manager -psn_0_1065220
501  8385  8310   0  1:26PM ttys000    0:00.00 grep ScanSnap

Now I'm going to quit this (via Terminal.app, same session, for further proof) by running:

kill 977

You notice that the syntax for the kill command is 'kill PID', and I used 977, because that's the PID reported by ps.

Now, lets check and see what is running after that kill command:

ps -eaf | grep 'ScanSnap'

Output:

501  8430  8310   0  1:28PM ttys000    0:00.00 grep ScanSnap

See? It's gone. That output you see... that's the fact that I'm grepping the ps output for the string, NOT the original process, or ANY process related to the app.

Today You Learned. Good day.