Thank you very much, Cenzontle!
That's interesting. I felt that 'get sent' might express the uncomfortable 'impact' on the recepient. In other words, it could imply the recepient is not comfortable getting those flowers.
To me the difference between those two is that 'gets' directs the attention to the act of sending the flowers, whereas 'is' directs it to the whole situation. I would probably use 'is' in your sentence.