Tracking pixels aren't for fingerprinting, they're just regular tracking. You can block them fairly easily (just block the 3rd party request to the known tracker). Fingerprinting is a lot more difficult to detect and prevent. Companies claiming they reserve the right to do it is a good reason to take precautions, but without insight into what is actually being done, that's hard to effectively do (without resorting to blocking all possible vectors, like Tor Browser).