Orders from someone new
First order ahead is paid now
Only their first, and only ordering from elsewhere
Orders waiting, per phone
At your shop. Finish one before starting another.
Someone at the counter is standing in front of you, so neither of these touches them. Both apply only to orders sent from elsewhere, and both aim at the behaviour rather than at anybody in particular.
Nobody is told they were suspected. A first-timer reads "this one is paid now, next time you can pay when you collect"; someone at the cap reads "you have 3 waiting — finish one and you can order again."
Neither of these touches anyone standing at your counter.