If your opponent does not measure and just declares that his ship is out of range, and then it comes to your time to shoot and it turns out you're actually in range, your opponent has missed an opportunity and you have to consent to allow him to perform his missed trigger.
Attacking is optional though. If they voluntarily decide not to shoot, that's not a missed opportunity, that's a choice. I'd feel no obligation to allow them to shoot at me if they initially declined the opportunity. Should we go back to actions and let him target lock me too? That was a missed opportunity.