I honestly had no clue you could pay for entrance to our national parks with a cc.

I "think" but I am not positive that it depends on what code is use for the type of purchase used, then it depends on the credit card issuer to decide if that falls as a cash advance or not, this I recall from my knowledge of cc processing (havent dealt with that in a long time)

Essentially there are purchases that are going to be a guaranteed cash advance (like transactions in casinos etc) , departure tax is a tax and therefore it makes sense to me to be treated as a cash advance, a entry fee to a park (movie etc) doesnt sound to me that it should be treated like that.