Cup holder false bottom for Airtag

My son is heading off to college, and the college he is attending has a history of bike thefts. I wanted to create a hidden AirTag spot that wasn't under the seat or on a reflector. My thought is that most bike thieves would check there. So I made a false bottom for his cup holder. The AirTag fits snugly in its spot without any other means. There are drainage slots for rainwater to funnel to the bottom drain of the cup holder. I positioned the AirTag at the top of the holder to minimize any water damage.
The false bottom is 80mm in diameter.
I printed this with black PLA with 50% infill.