Watching the Watcher
Manipulative people, or Two Legged Snakes (as I like to call them), if they are of the intelligent variety are watching you to see what sort or ‘trust cues’ are important to you in determining who you let your walls down for.
For example, if you’re on a date with a potentially manipulative person (TLS) and he observes you smiling approvingly at a father interacting positively with his young child the TLS may make a point of being kind to children as a way to gain your trust.
If you’re a ‘look a person in the eyes when you talk to them, firm handshake, straight shooting type’ a bright TLS will pick up on this immediately and will ironically give you this no BS behavior in spades.
Taking your time is a great defense against this type of manipulator because the manipulative person’s inconsistency and insincerity will surface fairly quickly to an observant eye. Also, watch out for a change in behavior after your display of a trust cue. Keeping in mind the first example, if your date soon after observing your approving smile found some way to be helpful to a child you’ve most likely uncovered a TLS, simply by watching the watcher.