Meanwhile, the cashier area will be normal for the customer to put money in front of her because of her might create embarrassment to an employee or potential employee receiving tips, no rules.
Usually the cashier to put money tip jar for customers. The tipping presence could create embarrassment to the employee. Or some may have rules that employees not get a tip.
Normally the cashier is for customers to put the tip jar. Because tipping before may create trouble for its employees. Or maybe there rules from the tip.