Bungie shows that a referee is eligible if they played TTK within 7 Days, but in FAQ (https://www.bungie.net/en/Help/Troubleshoot?oid=13962) it shows that they cant play TTK before accepting a referral. It also states in the "How to Create a Link" to play TTK. (https://www.bungie.net/en/Help/Troubleshoot?oid=14003). Then it states here (https://www.bungie.net/en/Help/Troubleshoot?oid=13997) that once they log in to TTK they are granted Vetern Status. However in there suggested ways of finding new players is to troll early missions and the tower for low level players.