This proves that it's not the fact that the enemy are equipped with lasers, it's the small size of the hostile craft that is the issue (the original script even said 'phasers', instead of 'lasers').The Outrageous Okona
WORF: Captain, they have locked lasers.
PICARD: Lasers?
RIKER: Regulations call for a Yellow Alert.
PICARD: It's too small of a craft to be of any threat to us. Do you agree, Lieutenant Worf?
WORF: That won't even penetrate our navigational deflector.
This proves that lasers CAN endanger the Enterprise D.Loud as a Whisper
WORF: I'm reading laser activity in the Solari Solar System!
RIKER: How concentrated is the activity?
WORF: It is localized -- and very intense.
RIKER: So much for the cease-fire.
PICARD: Open hailing frequencies.
WORF: I can establish voice only.
PICARD: This is Captain Jean-Luc Picard, commander of the Federation starship USS Enterprise. If you continue to violate the rules by breaking the cease-fire, I will abort this mission.
FIRST LEADER: You have no jurisdiction here, Picard. Where is Riva?
PICARD: Riva is in charge of the summit. I command the ship that brings him. I will not endanger my ship under any circumstances.
What more proof do you need?