I have to respectfully disagree.  While I think it's nice to give gifts to these people and show your gratitude, I don't think it should be expected and I don't think it should be frowned upon if some choose not to contribute - for whatever reason.  These people are working and they're paid for their work.  

Again, I have no issue with giving gifts, but I don't believe they should be compulsory.  And gifts should never be relied upon as income.  

Just my opinion.