Police can swipe your plastic now. No, not swipe as in steal. But they can swipe your card to read the magnetic strip on the back, and it is not a Fourth Amendment violation (illegal search/seizure) to do so. At least not yet. The 8th Circuit Court of Appeals decision did leave open the possibility a defendant might show, in a case with the right facts, that such a swipe would be a privacy violation.
So, to sum up recent developments:
Police can swipe the magnetic strip on your credit cards. http://arstechnica.com/tech-policy/2016/06/appeals-court-rules-cops-can-legally-search-a-seized-credit-card-with-no-warrant/
Police can read the data on your prepaid gift/debit card and seize the money from these cards and/or accounts. https://www.washingtonpost.com/news/the-watch/wp/2016/06/08/new-frontiers-in-asset-forfeiture/
Police can require you to unlock your phone or other device with your fingerprint, even though they cannot require you to give them your passcode. http://www.inc.com/will-yakowicz/why-biometrics-are-bad-for-your-constitutional-rights.html
Be very afraid.
