In the UK they all seem to be free, or certainly not automatically billed. Destination chargers are generally for people using the destination and aren't just a "turn up and use" type thing when you're passing (you weren't I know), although if they're at the place you're visiting then, in the absence of signage telling you otherwise, just plug in and use. Places are increasingly starting to charge for their use, often just a fixed fee as metering can be difficult, and thats maybe a sign of rising energy costs. It's probably best not to see them as anything special for Tesla owners, they're just like any other destination charger and the same logic dictates, ie check the signs and be respectful.
As an aside, there is usually more than one at any particular location, some will have white writing on a red background and will only work on a Tesla. others will have red writing on a white background and will work on any EV. If you're being charitable then use the Tesla specific one if you have a choice leaving the other free for an other EV.