Howdy, I couldn’t see any information on how to contribute, but I thought it might be good to add some checks for affiliate links. I whipped up this quick patch for it.

If there is a git repo or trac instance or some better way to contribute, happy to contribute there instead.

Index: checks/badthings.php
===================================================================
--- checks/badthings.php	(revision 2355373)
+++ checks/badthings.php	(working copy)
@@ -14,7 +14,9 @@
 			'/uudecode/ims' => __( 'uudecode() is not allowed', 'theme-check' ),
 			'/str_rot13/ims' => __( 'str_rot13() is not allowed', 'theme-check' ),
 			'/cx=[0-9]{21}:[a-z0-9]{10}/' => __( 'Google search code detected', 'theme-check' ),
-			'/pub-[0-9]{16}/i' => __( 'Google advertising code detected', 'theme-check' )
+			'/pub-[0-9]{16}/i' => __( 'Google advertising code detected', 'theme-check' ),
+			'/sharesale/i' => __( 'Sharesale affiliate link detected', 'theme-check' ),
+			'/affiliate_id/i' => __( 'Potential affiliate link detected', 'theme-check' ),
 			);
 
 		$grep = '';