Sorry if I got a little short in my answer. I got in a heated argument with a guy buying SIC time at a 135 cargo operator that used metros. When I showed him the TCDS for the aircraft and dug up the OPS SPEC to show him that what he was logging was not legal (guy he was flying with did not have an ATP or current MEI). Ride alongs are neat, but nothing ticks me off more than people that log what isn't legal trying to get an edge. You might as well just make it up.

You can "log" whatever you wish. Remember though, that might come back to haunt you. That person sitting on the other side of the table might have 4000 hours in the MU-2 you did a couple rides in working the radios for the owner and why it was logged as SIC. That could get ugly.

The FARs are pretty clear in what you should log for aeronautical experience pertaining to ratings and currency.