Too honest?

I went to Costco and bought a 1/4oz Maple. I went to the Merchandise Pickup area and one of their people went into the room to get my coin. Lady walked out and handed me a 10g RCM bar. I told the lady I had asked and paid for a 1/4oz coin. A different version of me would have silently thanked her for the extra couple hundred bucks and left. Current me didn’t want her getting in trouble and doesn’t want the bad karma. What would you have done?

I went to Costco and bought a 1/4oz Maple. I went to the Merchandise Pickup area and one of their people went into the room to get my coin. Lady walked out and handed me a 10g RCM bar. I told the lady I had asked and paid for a 1/4oz coin. A different version of me would have silently thanked her for the extra couple hundred bucks and left. Current me didn’t want her getting in trouble and doesn’t want the bad karma. What would you have done?