A shield for cops would be a pretty nice thing, but it should have some limitation like: if you use the shield you can't use M4, AK47, Sniper or any weapons that need 2 hands in game + you can't have dual weapons (sawn-off, colts and etc), it could be protective for like 5-10 bullets, nothing more.
A shield is a nice thing apart from it being a cosmetic item it could have some advantages and disadvantages when equipped.
I would honestly put it for riot purposes (althought none occur). Recieving 30% less damage from everything but only available to hold throwables/melee weapons.
Nobody can escape their sins, everyone gets punished whether it takes a day or an eternity.
You can change who you are, but you cannot run from yourself.

xVikrant wrote:
Not possible in SA-MP. There are shields but they don't have their own collisions. You can find a shield.dff and shield.txd in SAMP.img. But, they are only for appearance. Moreover, It's SA-MP, not GTA Online or so.
Shield is just an object, not taking damage from a distance can be done with simple coding with 'if-else' statement, object is just for visuals.
Red_DragoN wrote:
Shield is just an object, not taking damage from a distance can be done with simple coding with 'if-else' statement, object is just for visuals.
Does it have its own collision?
Not sure but it isn't even that important anyways.
I disagree with this. Cops are currently very overpowered imo, this would make the situation even worse.