I am an associational Baptist. That means I believe that the Baptist church to which I belong can and should participate with other churches of like faith and order in fellowship and outreach. Of course all this associational effort is "at will" of each individual church.
For the last 12 years, I have belonged to churches that associate with other churches under the name of the American Baptist Association. I am very fond of the association and for the most part consider myself an ABA'er. But I do struggle with the idea that I am beholden to this association. Jesus established the Church as an institution, not an association. Those who participate in ABA works would certianly agree with me on that point.
Now, just to be clear, I am a Landmark Baptist. I believe that there are certain characteristics that make the Lord's churches distinct from other religious societies and I believe that most churches that associate with the American Baptist Association, the Baptist Missionary Association, and the Southern Baptist Convention bear these marks. Also many independent Baptist churches (though they don't formally associate) can be recognized by these distinctions.
So the question follows that if the Lord's churches exist outside the bounds of the ABA (which they certainly do), then should the Lord's minister feel timidity about service outside that association? The short (and easy) answer is that the man of God should do whatever God wills for him. That said, there are real consequences. Some churches in the ABA might be wary of a preacher who had been preaching outside of the association.
To bring the point home, I am currently not pastoring a church. It was mentioned to me that the Southern Baptist Church down the road was without a preacher by someone who visits there. I assume an invitation to preach might have followed had I showed any interest, but I didn't. I basically never turn down opportunities to preach. So why do it here? I recognize them as a valid New Testament Church. (As far as I know, they may very well do closed communion), but I dismissed it based on associational lines. And out of fear. Fear of being looked at funny by my brethren. Fear of "tainting" my name by crossing those lines.
I'm not saying I agree with the Southern Baptist Convention at every point (I'm not a universalist, I reject open communion, I reject alien immersion - all things that are seemingly "creeping in" to SBC), but why should a church that I (and most ABA churches) would gladly accept a letter from be without preaching based on fear?