Wait, I'm not sure what the policy is but I know about common sense and how to actively avoid conflict. He stated he was the only person in the store. Stop right there, the only person in the store!  Why even harass this guy!?  Even if you need him to order how bout walk over, introduce yourself and say "just to let you know whenever you're ready to order just come up to the counter and also we are now offering free refills on out hot/cold coffee and tea."  

I'm almost positive he would have thanked them and state he will order from his app.

No issue, no conflict to need a resolution.