Why do pro golf caddies let the pin rest on the green and then lean on it putting an indentation in the green?

As a young caddie we were taught to leave the pin off the green or if on the green, place the pin bottom on top of your shoe and also not stand in the putter's view. When I watch the pros I see these mistakes all the time. The green is considered sacred. With what the pro-caddies are being paid you would think they would know better. Maybe I should go into the caddie business. Answer me please why these rules are so relaxed?