Do not scan QR code you find online, only scan when paying to another crypto wallet or you want to sell your BTC on an exchange, QR codes can come with malicious things too.
The advice not to scan QR codes found online is wise. I myself am also very careful in this regard because threats can come at any time from unknown QR codes. The best solution is that I only pay cash although other options are also available using the QR code payment menu.
I don't think that anyone that understand security on his wallet, will use his wallet that has his bitcoin to play with by scanning any how QR code because the only time that a QR code is to be scanned is when you want to transfer your bitcoin to another wallet address, this is when you are to scan, so I don't see why someone will use his bitcoin wallet to start scanning anything online.
The hardware wallet is safe but the safety of your bitcoin lies in your hands, if you take precautions to keep your wallet safe, your hardware wallet will be safe but if you lose guard your hardware wallet, then you wallet will be compromise.