I've not had a guest bothered by this (there have been plenty of late sleepers and nappers!), it's never affected me, and there are earplugs in the room for light sleepers (I supply them for trash pick up day).
I always check in with and want to hear how my guests are doing - if there is anything I can do to make someone more comfortable, I will, so I wish I knew about Laura's ideas while she was here. Guest's suggestions are valuable, and while no one has mentioned this before (there are two windows to let in the ocean breeze and a fan in the room), we will look into ceiling fans. Airbnb only allows one flat rate for a cleaning fee, and the same thorough cleaning job is done regardless of how long a guest stays. Thank you for the kind words, as well!