Hey there,
I oversee the securty team of a Church in Australia. I wasn't involved in the setup of our team, but let's see if this helps.
1. It depends who is giving the opposition. The approval and direction about a security team needs to be the decision from the Senior Pastor/Board/Eldership team (whoever are the ones that make the key Church decisions). Anyone else needs to learn to submit to the leadership of the Church. If it is the decision makers – then you need to walk through their concerns together and find common ground. Most people's perception of security is far from what it can be within the Church environment and therefore it's the challenge of those seeking to establish it to frame the safe and secure environment with the vision of the Church. ie From a security perspective, I could create a barricade between the Pastor(s) and church members [it's the easiest way to keep the pastor safe]; but if the vision of the House is to connect and build relationship with their congregation then there's a conflict.
2. Reasons Given: Most people need the why factor. Getting info off this site relating to risk assessment and videos on how to approach Church leadership should help out in this area.
3. I am on Church staff now however I wasn't when I started in my security role. Nor is my paid role related to the security aspect of my contribution to Church.
If I can give final words of advise a) Pray – God is the head of all things and needs to be the guidance. He also has the ability to work on the other people involved :P b) Communication – Putting new wine in new skins can be a challenge but the more talking and relationship building that goes on, the less anxiety there will be.
Oxox