i've always questioned it myself, i've ridden w/o but i think a rider or two at some point told me that there was a valid reason for it, (pushing gas fumes up from bottom of the hull?) i think it maybe redirects water somehow as well. mine has one now and i'll leave it in, but i've had many days where I took it out and set it in a corner while charging the battery, forgot about it and rode for 2-3 weeks before realizing it was sitting on the corner of the workbench.