Shemar

EMR

First thing check with the condominium that you can install the panel.
We now cover our panel when away in the summer months.
The system is equipped with a safety release valve in the event of overheating but still better to cover..
Also make sure the electric heater element is also switched off.

liveaboard

You need to get your nomenclature right or people will be confused; "Solar panel" usually means an electricity generating photovoltaic panel.
What you're talking about is a "solar collector" for heating water.

Technically, both can be correctly called "solar panel" and to make things worse, they look very similar.

Score76

The hot water panels won't overheat, as another poster has already said, they have a release valve at typically 90C. Bare in mind though that in summer, if you're not using the water you'll still be paying for the water itself, or for the electric pump if you're not on mains, so better to cover as well.

You also need to consider where the 90C water will go, not a great idea to rely on the normal flat roof drainage (terracotta pipe onto somewhere below usually), that will easily scold anything it lands on. After adding a drain pipe that melted and went like cheese the first time it got used, I then had the outflow pipe extended down to ground level and fed into a soak away.

Shemar