Fencer: I don't care what color. Any color.

You say "people" complained, but as far as I can tell there was only one: Walter Montego. I agree with him, by the way, that the best solution would be to let each user choose a color for each game type.

In the absence of user-configurable colors, I think it's best to have a different color for each game with nonstandard rules or objectives.

It's true that we could function without any colored borders, by taking the extra half-second to look at the game name. But the current situation, in which almost every nonstandard game has its own color but one does not, is the worst system I can think of. The colored borders used for Berolina Chess, Ambiguous Chess, Loop Chess, etc., lead one to expect that any game without such a border is played with standard rules and objectives. And while it only takes half a second to glance at the game name, one has to make a conscious effort to do this.