To dunk or not to dunk

Last night in my small group the topic came up about church membership. One of our fellows decided one sunday to "tick the box" for church membership.
He has come from an Anglican church background, and was baptised when he was 6. He received a phone call from our pastor about the membership and was asked whether he had had an "emergent" baptism. (where your dunked under water). He said "no" but if thats something I have to do, then I'll do it.
He was asking our group what we thought. The discussion that followed was very interesting. Isn't baptism something of the heart? Isnt is something that you make in your christian journey, and not something you have to do to become a member? I asked him about when he was baptised at 6. His father was the Anglican Priest at his church and wouldnt baptise him until he understood what it meant. It wasnt a sprinkling it was liked cupped over his head. Thats the best way I can describe it.
We all sort of decided that he shouldn't be baptised again if he felt that he had already made that public commitment. But here is where it gets tricky. Because he came from another denomination, does his baptism count? Do we recognise other peoples/denominations way of doing things? I personally dont believe he should have to be baptised again if he feels that he already publically announced Christ when he was 6. I also don't believe that he should therefore NOT be allowed to become a member because the Church's "constitution" says it has to be an emergent baptism.
The constitution at Church says that Bull Creek members have to be Emergent baptised
(sorry if Im using or spelling emergent wrong). Does that then mean, that if someone was baptised in a different way other than that, not allowed to become a member? What if someone came from another country, didnt have a baptismal, or a bath, and they had to baptise themselves (has happened in some countries) or whatever the circumstance. Would we not accept them?
The next problem I have is, if someone wants to become a member but is not ready for baptism, are they then not allowed to become members? I dont think anyone should be allowed to tell another person when they have to be baptised. It is a personal decision. One of the girls in our small group described it really well. She said it's like marriage. You don't commit to the person on the wedding day. It is a whole process through the engagement. In the end, the ceremony on the day is your public display of committment.
There are so many for's and against's. The line can get blurry. It is also hard when a constitution puts the two things (membership and baptism) in the same sentence. It should probably be, "Here at Bull Creek we baptise this way...".
I am interested to see what different people think on these issues.
Have fun!