To avoid being ripped off in hotels and other public places, the experts stress that you should watch your step and your dress:

* Keep to open, well-lighted and well-populated areas. Never enter a blind or enclosed area, especially one with ready egress to the street.

* Don't expect a hotel to look out for your safety; the New York hotel justified existence of its trap by claiming fire regulations required closed doors at either end.

* Stay in the crowd, but keep a safe distance between yourself and others, and literally go out of your way to avoid anyone who looks suspicious. Forget all you were taught about not creating scenes, and shout for help the minute you think you are in danger.

* Watch out for men (or women) who carry man-bags. Those big satchels can swallow a purse or package without a trace.

* Dress down; wear nothing that will attract attention. Move purposefully, as though you are about to join someone waiting just around the corner.

* Wear your valuables on your person, concealed. Most jewelry can be worn under clothing. Carry a minimum of credit cards and cash, and find a way to keep them on your person instead of in a handbag or outside pocket. Ingenious "travelers' caches" are avaiable that fit around your waist, on your leg, under your arm. Find them in gift shops, or look for ads in travel magazines. Also available by mail from Wahlstron Travel Aids, 21225 Nashville St., Chatsworth, Calif. 91311, or (213) 341-7241.

* Exercise caution when emerging from express elevators, especially if they serve an exclusive part of the hotel. But by all means use express elevators, to avoid being accosted by anyone getting on at an intermediate floor.