I"M REPORTING BACK MY ACTUAL JETBLUE EXPERIENCE: (Sept 2019)
I woke this thread up a few posts back when I realized my already packed and ready to go bike box was larger than the Jetblue published limits.
I can report that the counter agent took the box without measuring or weighing it and he used his discretion to waive the $30 checked bag fee, charging me just the $100 bike fee (It should have been $30 bag fee, plus $100 bike fee). He was very pleasant and everything went smoothly.