Paypal halted a transaction because it contained the word "Cuba"

My wife, Carla Sinclair, is editor of Wink Books. Yesterday, she used Paypal to pay Ben Marks his fee for reviewing a photo book published by Taschen called "Castro's Cuba: An American Journalist's Inside Look at Cuba 1959-1969."

Carla included a message to Ben in the Paypal transaction, which read, "Hi Ben – Your Castro's Cuba review is up! Thanks so much! Carla."

As soon as she pressed the send button, she got a pop-up message on the PayPal site that informed her that the payment was being held for review. This had never happened before and she had no idea why PayPal was holding up the transaction.

Last night, an email arrived from PayPal. It turns out, the problem arose because Carla's message included the forbidden word "Cuba" (and/or possibly "Castro").

Here's the email from PayPal:

As part of our security measures, we regularly screen activity in the
PayPal system. During a recent screening, we noticed an issue regarding
your account.

PayPal's Compliance Department has reviewed your account and identified
activity that may be in violation of United States regulations administered
by the Department of the Treasury's Office of Foreign Assets Control (OFAC).

PayPal is committed to complying with and meeting its global regulatory
obligations. One obligation is to ensure that our customers, merchants, and
partners are also in compliance with applicable laws and regulations,
including those set forth by OFAC, in their use of PayPal.

To ensure that activity and transactions comply with current regulations,
PayPal is requesting that you provide the following information via email

1. Purpose of payment 0B463347YT949791N attempted on August 16, 2016
in the amount of $30.00USD, including a complete and detailed explanation
of the goods or services you intended to purchase. Please also explain the
transaction message: "Hi Ben – Your Castro's Cuba review is up! Thanks so
much! Carla."

Please go to our Resolution Center to provide this information. To find the
Resolution Center, log in to your account and click the Resolution Center
subtab. Click Resolve under the Action column and follow the instructions.

If we don't hear from you by September 01, 2016, we will limit what you can
do with your account until the issue is resolved.

The lesson: don't use forbidden words when sending someone money via PayPal. Better yet, use Bitcoin instead.

I wonder what other words will trigger this kind of action?