Unfortunately, more often than not, it is a thoughtless formality. Many will offer up a wai, then stab you in the back.
Unfortunately, with ATM usage, most UK institutions also add a substantial charge.
This is one of Thai customs that I wish will endure! And I think it will.
That's what turns me off about about carrying TC! I'm thinking the cost of cashing them can already buy me a good meal, and I am budget conscious. However,
Although more safe, TCs now incur 153 baht charge for cashing them, about 3 GBP per transaction.