Yes, I could see it happening, but that doesn't mean I support such a ruling.
A smart umpire will keep on the coaches to keep it moving and remind them of an umpire's option of [/b]judging[/b] their actions to be intentional and that a forfeit is not out of the realm. However, they would also be smart enough to commit to making such a ruling.
I've also seen umpires stop the clock. Personally, I prefer the umpire which all of a sudden realizes how dark it has become, or how the condition of the field has deteriorated during the game and call it for safety reasons.