Hi guys,
just transferred in AMS a week back and I've seen the signs they put up in the lounge, informing that the access for Petroleum club members only applies when you are flying onward on AF/KL metal.
I specifically asked that means a Petroleum club member won't have access if the onward flight is e.g. on Delta metal with a KL flight number and they confirmed there won't be lounge access in that case. Lady said that has always been the rule, but it wasn't enforced in the past.
Cheers
Natcho