I agree with that post Yoshi.
What makes the shield unstoppable? When it's in the hands of an extremely good player with fast reflexes and a cool head, and he knows what he's doing (when to pop out and shoot, etc) he will ALWAYS beat a player of equal skill wielding a colt/ak47/mp5/famas.
Not to mention that, but someone with the shield can be the "eyes" of a CT team, and if he plays his cards right, he can flawlessly scout where the T team is going on maps like dust2. Half the fun of playing T on dust2 was to trick CT and keep them in the dark as long as possible, before finally attempting to plant the bomb. But with a shield someone can step right up to the middle double doors and see if T goes left or right initially, and also have continuous line of sight to the catwalk, while being completely immune to 95% of the weapons in the entire game. CT gains not only a combat advantage, but a huge LOS advantage that they did not hold in past. Obviously this disturbs the game balance that the devs took so long to create.
These are not the only reasons the shield is banned - it's been bugged on and off since release, and it just isn't fair to give the CT this advantage, especially due to the defensives advantages they already hold in tournament play.
The flashbangs in source are IMHO imbalanced as well, but not everyone would back me up on this one. They are much harder to counter in Source, imo 1.6 was perfectly balanced and changed the the mechanics of flashbangs really messed up the rest of the game. (Now when you turn away, you are still partially blinded and can lose sound, which is so incredibly important.)
(Mort: no one plays cs_ maps in competition, so I won't overanalyze the use of shields in that context :))
When I play in a pub, I'm not always looking at the team score. In a scrim or match, yeah of course - ya gotta be ready to "take one for the team", and run away and save that awp/ak/colt. But sometimes in a pub all I do will be AWP or practice with some other gun, and that's so I can practice to use it in matches. Sometimes if a match goes well I'll be using the AWP for 3/4 of the game. If I'm only used to using it once every 6 rounds because I don't want to seem cheesy, well we just aren't going to win
Of course sometimes I'm just playing with friends, intoxicated or whatever, and just there for a laugh. I'd say as long as you are not there solely to grief other players, play however you want to play CS in pubs, and have fun doing it.
This is my opinion.