The 'tea tasting' or 'massage' scam
The FCDO describes it directly: friendly strangers invite you to a bar, to drink tea or have a massage, and the establishment then demands a large fee. It warns this can be followed by threats, violence or credit-card fraud.
Red flag — An unplanned invitation from a stranger in a tourist area that ends at a venue you did not choose. Decline before you sit down, not after the bill arrives.