When paying with a credit card, of course, you will be able to double dip, as the credit card program will still accrue points into whatever program it is attached to. (austravelpoints.com)
The way they can do this is by requiring a minimum purchase amount if paying with credit card. (blog.wealth-steps.com)
The solution: avoid the problem altogether by paying with a credit card for the best exchange rate, but check that receipt carefully! (travelinsurancereview.net)