The social consequences of mis-use of lunch/dinner and supper/dinner/tea are deep. Don't you believe otherwise. People have been hounded out of Yorkshire for over use of sinister words like 'lunch'. The only way you can get away with using the word
lunch round these parts is to add
-eon meat to the end of it. And even then someone will ask you if you're too stuck up for Spam.
The matter is only slightly less dangerous than all the pitfalls to be had when using napkins (I avoid this by wiping me gob on me sleeve).