I understand your point MrP but did you realise that in most Muslim countries it's viewed as being very rude to leave an empty plate or glass infront of a someone. They would rather have you sit there with nothing infront of you than leave you with empty plates bowls and glasses. It's a custom not a ploy to make you buy more. You'll find this is done in a Turkish home too.
Laurence
I had a bread roll, some chicken & salad on my plate. I made this into a chicken salad roll & the waiter whipped the plate away while I was only just over half way through the roll. Yes, the plate was empty, but the food was in my hands & I did need to put it down on something to sip my drink or just have a breather.
That one took the mick, my husband told him to put the plate back, which he did, but looked afronted.