The many options may tempt you to use QR codes even when they make little sense. In such cases, QR codes can quickly turn into a gimmick and users will not interact with the codes.
Furthermore, a QR code must be placed in a static, stationary location so that the graphic can be read. Placement on moving objects, such as a vehicle, makes scanning impossible.
Lastly, QR codes also have the potential for security risks. In public places, QR codes can be pasted over or otherwise manipulated: Anyone scanning these codes runs the risk of being directed to a problematic URL, and it’s difficult to tell at first glance whether or not you’ve being misled. Only once you come close up to the code can you see whether it’s been taped over.
Not all available scanning apps will show users the website linked to the code. Therefore, pay attention to where you’re being directed before you confirm this in the app. Also be careful with link shortening such as bit.ly: This can disguise the target URL. Therefore, always consider whether the code is secure or not.