I know airports and airlines have rules but what annoys me is that some seem to go out there way to catch you out and charge you extra. Spell a name wrong when you book and then try to change it... kerching. Turn up with hand baggage half an inch to long.... kerching. Ryanair are one of the airlines appealing about some new guidance allowing more hand baggage allowance and the owner has made it clear that staff will be incentivised to raise more money in such ways.
Things like that are generally at the budget end of the market. They have their place and they work very well for some. Just need to go in with your eyes wide open.
Do this in Germany too with curry ketchup. In Norway it’s curry powder they put on chips with curry ketchup. I asked if my cousins had vinegar when we came home late from the club one early morning, they couldn’t believe it, vinegar on chips! Mind you, I put vinegar on my kebab too!