I had a debate with friends based on the wording on the card. I believe because the way it is written, I can give a keeper and immediately take it back instead of taking one of theirs.
ACTION: Exchange Keepers
Give an opponent a keeper. Take a keeper from an opponent. If only one player has a keeper or no keepers are in play do nothing.
Notes: The wording has been revised in newer editions I understand the intention of the card, but believe there is a loophole in the rule.