Hamlet, to your question of { I asked a salesman at a gents outfitters a few years ago why they don't now ask if they can help the customer instead of asking "are you alright there?" The reply was"we aren't allowed to ask that anymore!" Why?" }...
it made me chuckle to read that they went from "may I help you?" to "are you alright there?" (thanks) but the Monty Python crew's 'salesmanship' training videos thought that when you ask a 'yes/no' question, it is very easy for the customer to say 'no', as in: 'may i help you? no!", and even if they said 'yes', one would need to ask yet another question as to the nature of the help. so they thought us to ask: "HOW may I help you?", assuming that there must be a way we can help them, after all they walked into the store, didn't they

..and it is an open ended question, forcing the customer to think creatively to dodge it. ....but to read that they were told "you are not allowed to say it" without an explanation or an alternative, they now babble yet another useless sentence, was funny.
as for Turkish merchants keeping an eye on you (not to help if you have questions, but to make sure you do not pocket anything) is indeed annoying. Having lived in the US for almost 30 years, this aspect now really bugs me too. I simply stare "öküz trene bakar gibi" back at them, until they look away or they ask me if i need help, then reply: "I am just looking, no need for you to follow me. I'll call you if I need help". Reminding them they need my business, not the other way around.