There should be a section a bit like League of legend.
For those you do not know, there is a Practice section (win / lost are not counted ) only leavers.
And there is a section for the ranked /stats.
Im only throwing this out of no-where but maybe doing 2 separate custom game could solve this.
Should not be too costy, they just need to copy /paste they code and add 1 button names Custom Game (unranked)
Only thing that change in the code is the stats tracking. (set to disabled)
They have remove already the skirmish button. so I guess re-adding another Button like Custom Game (unranked) wont be costy.
So with this new can play with pro and play mixed because if the PRO lose, stats are not gona be toutched.
Bottom line, People who their stats are important can play in the ranked custom game and have some real challenge there.
And the other one just wanting a great a peacefull time / practicing / testing stuff, the Custom Games (unranked)
Sorry for my bad english I had verry little time to correct my grammar.