There is a lot of discussion around the use of riot shields in airsoft. The last thing you want to see when you hit someone with your airsoft M16 is that he keeps walking with a big smile on his face protected by a shield.
Those that are for it argument that riot shields also are used in real life and therefore also in airsoft. Although I can follow this in CQB it is absurd in open field. Our armed forces don't carry around these shields in Iraq or Afghanistan.
Those that are against it argument that riot shields are not bullet proof, only bullet resistant. This is correct. That is why there have to be clear rules in a CQB arena.
We all agree that hitting a riot shield with a bb coming from an Airsoft M16 is pointless.
In real life though you can be very sure that after you get hit by a 9mm coming from a MP5 you'll be looking at the ceiling. Even if the shield does not get breached the impact will probably be too great to continue to fight. These shields were designed to increase the survivability. It won't guarantee it.
Some want to completely ban the shields from airsoft because it has a negative impact on airsoft as a sport. Personally I agree. Firstly for me it is all about speed and technique and the shield takes this away. Second. I would like to see the face of a guy or girl who gets hit with a real 9mm. Not to speak about several impacts.
In the end allowing or banning the shields is up to the organizers of an event. Disregarding my personal feeling towards shields in airsoft the following questions come to mind. If you allow the shield you will have to have an agreement on how it can be used. Will you allow it without limitations? Will you allow it for a certain number of hits? How are you going to implement this? Will you allow it for a certain amount of time after entering a room in order to mimic the bullet resistance aspect versus bullet proof?
Make sure that these rules are agreed upon before the event takes place and communicate this to the participators. Put it in the mails, posters, flyers.....
Be clear about it to avoid the disappointment of players with false hope.
Clear rules make good friends. Good luck and good hunting.