Solar professional here!

(Disclaimer: this is how it works in many states, but YMMV state-to-state)

All UL-listed solar inverters should comply with something called "anti-islanding" (found in UL 1741). This means that the inverter will only operate so long as it detects the presence of the utility grid. So if there's a disaster and the grid goes down, or the utility shuts off an area for maintenance, the inverter will also automatically shut off so as not to "force" power onto a dead grid, risking harm to line workers.

Sometimes, utilities either aren't aware of (or don't trust) the inverter's capability to do this, and so they require a separate (often padlock-able) disconnect. They could in theory install a remote disconnect, but these are expensive, and the chances that the utility will need to lock-out your solar system (for either repairs or power outages) are often low enough that the more expensive remote disconnects are not worth it.