What are those glowing blue shields in Resident Evil 5 for

It changes how your partner reacts when you shoot them.

With Attack Reaction: ON, I remember that your partner would react to the shots as normal, they will hit your partner, your partner will shout\scream\bleed ect.

With Attack Reaction: OFF, Your partner will not react in any way if you shoot them. No blood, ect, and the bullet will pass right through them.

Regardless of which option you choose, you can never hurt your partner, it's visual effects only.

No, you can't get infinite gold eggs without hacking