All airlines clearly publish their baggage rules, and this has been since time immemorial. However, enforcement of the said baggage rules is, and can be, inconsistent and can vary depending on location and also loads on flights as well as how much of a hurry the agents are to get the flight off the gate for an on time departure, so this is not a QR issue in particular, but I would proffer it to be industrywide phenomenon. I have seen on numerous occasions flights where either the check-in agents or gate agents are zealously enforcing baggage weight limits, and at other times, same flight, same airline, different date, no one even bothers. It's just difficult to say, though the LCC's obviously have a greater vested interest in making sure bag limits are adhered to as its a significant revenue stream for them as part of their business model. Anecdotally, I was told by a BA crew member during a friendly conversation during a crew break they were having at a hotel bar that most American and European airline unions do not allow their members to handle and lift more than the stated baggage limits for safety reasons as well as insurance coverage, as back and other injuries increase as airline staff have to handle heavier loads.