I suppose if they are happy to do it....
Problem is a lot of them want it both ways - In my paid job (for DTEI) I have, on several occasions at fatal crashes, offered to CFS crews doing traffic control/detour duty, to replace them with DTEI staff and been told 'No, it's ok, we don't want the help etc'.
That's fine until several hours later when DTEI are being slated for not allowing the CFS guys to go home, then you usually get the 'we are only volunteers you know' line which drives me nuts......
Or when we offer to provide staff with the appropriate equipment to clear up after a crash to be told that the crews on site will deal with it - to then get called 5 or 6 hours later, often in the middle of the night, again being criticised for not turning up to assist the volunteers......
Don't get me wrong, it works better than this on most occasions and I certainly now make sure I'm speaking to the right people when dealing with the issues.....