Generally, I reserve congradulating a team-mate when I know they deserve it. When I see somebody land multiple kills in a less than uber ride, I think they did a great job even if some of the kills may have been proxys. In my opinion, when somebody lands some kills in a Hurricane MkI or a C205 in a LW arena, the definately deserve a "WTG". Regardless of what chess piece they fly for.
Lately I've been sending out more Salutes too.
Just my .02
Obie