tip for service OR tip service
This morning, I browsed an English websites and found below sentence written by a netizen. I have a question regarding it:

In a forum, the net users are talking about whether or not tipping for delivery food. One user said "I tip good service, and don't tip bad service. I never feel obligated to tip." I think there should be a "for " after "tip", that is "tip for good service and don't tip for bad service", because "tip" should be followed directly by someone. Am I correct?

Question

tip for service OR tip service
This morning, I browsed an English websites and found below sentence written by a netizen. I have a question regarding it:

In a forum, the net users are talking about whether or not tipping for delivery food. One user said "I tip good service, and don't tip bad service. I never feel obligated to tip." I think there should be a "for " after "tip", that is "tip for good service and don't tip for bad service", because  "tip" should be followed directly by someone. Am I correct?

Answer

There are two ways of looking at this:

"I tip good service" - "tip" is transitive, and has a similar meaning to "reward" here.

"I tip for good service" - "tip" is intransitive (no object, so you use a preposition), and "for good service" gives us the reason why you tip.

Some verbs can be transitive or intransitive.  Both possibilities are correct, but the meaning is slightly different.

Answer

It reads correctly either way.  In English, we often omit prepositions and other modifiers that would be obligatory in other languages.