Scanning doesn't place the call
This is the most common misunderstanding. Scanning a phone QR doesn't start a call — it opens the dialer with the number filled in. The person still has to press the call button to actually dial.
That means an accidental scan never results in an unwanted call. It also means wording like "scan to be connected" isn't accurate; something like "scan, then press call" sets the right expectation.
You add the country code yourself
For a code used only domestically, type the number the way you normally write it — the generator strips hyphens and spaces and keeps the digits.
If it might be scanned from abroad, add the country code and drop the leading zero, like +82 10 1234 5678. The generator preserves a leading + and tidies up the rest of the punctuation, but dropping that zero is on you. Type +82 010… and the zero stays, producing a number that won't connect.
Where it works well
A contact card on a car dashboard is the classic case, and it suits shop enquiries, "back in 10 minutes" notes, and on-site contacts too — anywhere a single call settles the matter. All the code does is wrap the number in a tel: link and hand it to the dialer of whatever scanned it. So the number stays out of the frame of a passing photo, but it is fully visible to anyone who does scan. Nothing about scanning is restricted to people who need you — point a camera at the code and the number is theirs.
If handing out your real number feels like too much, enter a virtual or alias number from your carrier or an app instead; the generator drops whatever digits you type into the tel: link, so any number behaves the same. It's also worth printing the number next to the code. Scanning isn't always practical, and not everyone uses QR codes.