I sent this question t o a well known halacha institute. This is how I worded the question:
Kvod Horav,
When is one obilgated to give a tip (i.e. waiter, delivery, camp
counselor) and when is it optional?
Thanks,
(name)
This is the answer I received:
(name),
Thank you so much for contacting us with this interesting inquiry. The answer to your inquiry is that generally one is not obligated to give a tip. However, one must be mindful of two things. In some circumstances a “tip” is part of the employee’s salary (camp counselor or waiter) and as such it should be paid the same as their salary. Additionally, one must be mindful of the potential chillul Hashem that could result if one does not properly tip an employee.
Hatzlacha Rabba,
—
(name of Rov)
(name of institute)
Obviously, consult you own posek, but it seems to me that it would be agreed upon by most.