Not even 600 miles...

Correct. But the pump comes with injectable slime that’s supposed to patch up to a 3/16” puncture. Larger than that or in the sidewall and you have to wait for the tow truck. Also others have reported that they only tow you to the nearest Honda dealer which isn’t that helpful after hours.
There are threads on what size doughnut spares fit but that takes up some trunk room.
There is also a thread on how to replace just the bottle of slime instead of the whole pump package to save $.

 

Does the Clarity 100% require a flatbed? I haven't checked the manual, just curious.

 

Yes! Page 571 of the manual says it’s the only way to tow the Clarity without damaging the drive system.

 

Yes, but the emergency response guide says “The preferred method is to use a flat-bed tow truck. If wheel lift equipment must be used, be sure to suspend the front wheels and release the parking brake.”

When I had my flat, the regular tow truck and had to call for a flatbed since I showed him p 571 of the manual. The flatbed driver was totally in the know and even knew how to keep it in neutral to get it loaded on the flatbed. He mentioned that a flatbed is always better, but it would have been fine to do the regular tow and if I’m ever stranded in the middle of nowhere and that’s what’s available, to use it.

 

When towing a Clarity with the rear wheels in contact with the road, the car's significant rear overhang increases the danger of the rear of the car coming into contact with the road or, more likely, a driveway. The Clarity's rear overhang also makes it trickier to load onto a flatbed truck, but that's a more easily controlled situation than towing with the rear wheels on the ground.