A church tipped my friends who work at a restaurant $0 on a $3,000 sandwich order.  For pick up.  Was the no tip fair?

FWIW, many people don't believe in tipping for take-out food. The tip is for the server, not any other staffers.

Tips are always optional, by definition.  The service is presumed to be already included in the prices on the menu. Otherwise, how can the management pay the servers the full minimum when nobody tips?

Anyone complaining about poor tips should probably find a different career.

The entire concept of tipping revolves around the customer subsidizing workers pay based on the quality of the workers service. Yet most people tip well, or don't, regardless of service. Typically, if the service is bad enough the customer will request a manager.  Otherwise most people tip, even if their waiter wasn't particularly fast or the food wasn't particularly good. They also don't tip more If the service was excellent. This is important, because it shows that we are conscious of the fact that our tips are necessary for adequate payment in regards to the work the server has done. 

With this in mind, I will say that tips are generally less common on pickup orders. They have historically constituted a minimal portion of a servers work and time, and therefore don't have much of an effect on their overall take home pay.

This changes when you take into consideration the current pandemic, and general loss of business at dine in establishments. Those workers have probably had their hours cut, and spend a much larger portion af their day filling pickup orders. It also changes when an order is very large, as it take a bigger chunk of time out of everyone's day to make and consolidate it.

If this was a location with traditional servers, who would normally be tipped in a dine in scenario, then your church should have tipped at least 10%. That was my go to before the pandemic on pickup at those types of establishments. Now that things have changed, I never tip less than 20% on a pickup order at a dine in restaurant. If I can't afford that then I should go buy and cook my own food.

No, that isn't fair or reasonable.

No wonder- only $3000? That's chump change!

Churches and Christians in general are known for being lousy tippers.  Many people will take a picture of the receipt, with specific info like credit card info marked out, and post it on social media to warn others about customers like this.