Greg old boy you just hit on the best accordion builder in the state of La. Mr C Jr. M A R T I N on the guitar and his grandson the great Joel Martin. Joel is a fine accordionist and has three or four cds out.

I agree with Randy, that Mr. Martin is building very good accordions for many years and his Grandson Joel is a very good accordionplayer.
I realy love the footstamping from Granddad and grandson
Not all the bands are doing backing up with the accordion during vocals or fiddle solo's.
I don't know if it is usual to do so ?
Or is it a matter of taste.
Some of the braves will know that I think and hope.
At link#2 and #3 examples with Octa Clark the Savoy Family band.
Marc Savoy stops playing during the fiddles and Octa the first time not and the second time he stopped.
If they play the accordion during fiddle or vocals it's not loud.

http://www.youtube.com/watch?v=wlv8PUyc1HQ&list=RD2FFVOELUIrs
This one is also an example of not playing at all.
Ray Abshire is also an example of not playing when the fiddle is going on,

Seconding effectively behind singers and other instruments in a band setting is all a matter of being tasteful, see Jimmy Breaux videos for examples, and an exercise in keeping it simple. Just remember that it's always easier to do too much than not enough and realize when its better to just hang back and let the other musicians do their thing.

I've been in a handful of bands where the accordion player thinks its his duty to play at all times and as a result of them either being deaf or wanting to be the center of attention at all times completely ruin songs by overplaying, playing too loud, and in many cases playing the wrong notes entirely while other instruments are taking their ride.

John

Cory McCauley and Wilson Savoy often play just the bass side, and with good effect.

Whatever you do please do not play the melody quietly along with the fiddle or steel. It is easy to overpower other instruments and plus nothing makes the hair stand up on your neck than when the accordion comes back in on time after the other rides. I agree with john and nedro a little in the right place goes a long way.

The only time you're allowed to play the melody along with the fiddle/steel is when you've been playing with the fiddle/steel player for more than 20 years