How strict are the airlines if one's bag is only 2cm bigger than the rule?

Question

If a carryon bag is 2cm bigger than the stated measurements I was curious as to how many airlines or which airlines in particular are known to enforce the rules most or all of the time? I presume a discount airliner such as Easyjet might even make you check your bag??

Edit: I'm not looking for anecdotes as to make it broad but more towards how do airliners run the bag checks? The methods? And, how these things might make easy to bypass or not. Not looking for something that just depends on the random mood of the checker but how each airline runs their checks every. single. time.

Answer 1

It depends, if the airline provides one of those "IF IT FITS" boxes to check the size of the carry on, then it might be refused. For example, EasyJet:

Anyway, 2 cm will not be easily noticed by bare eyes, so if the airline does not have the baggage checker at the gate I would take the chance as long as the weight is within the limit. Remember, if the airline has the baggage checker, it is better to pay for the extra size online, it will be much cheaper than paying at the gate.