Calling BC when you can't see the line

[Back In The Saddle]

Had a game in a gym where the interior of the jump circle was painted a single, contrasting color and completely obscured the division line. Player dribbles from BC to FC and then back near where the line should have been. He almost certainly stepped on "the line" with his heel. I didn't call it because I didn't feel I could justify the call. Or, more correctly, I didn't feel that I could judge accurately every time it might happen, and I didn't want to set a precedent.

My question: should I have called it, since I'm pretty sure he was on/over the line by 3-4 inches? Or was I right to pass on this call?

The only precedent I can think of is that if there is no 3-point line painted on the floor, you don't have any 3 point shots. Even if you know the shooter was above the top of the key.

On the other hand, if the dribbler had crossed the line by 3 feet, I would have had to call it.