You wouldn't deserve any thanks That rule doesn't exist I spent time looking at it rather than hiding behind a phone, but I did take a photo too. Crowds were busy though so I stood on some grumpy blokes foot so I could get a better shot
I did feel a bit hypocritical stood with a camera taking a knowingly ironic photo of lots of people taking photos, but as Ernie says it's a hugely un-aesthetic experience seeing the Mona Lisa
Glad I was there in 1969. No crowds or prevention of taking photos. Was there for the riots in 1975(?) going to England v France RU game. Dived into the nearest bar out of the way.