I just recived the following from CAP on Crime and I am sure they don't mind I share it on the forum with travellers to Costa Rica:
1. During your stay here use caution when contacting unknown people.
2. When swimming or playing in the ocean, make sure someone is watching your valuables.
3. Use caution when visiting remote locations or isolated beaches.
4. When in restaurants, markets, or other public areas NEVER leave your valuables unattended.
5. When you travel by car, always lock the doors, and never leave your personal items in sight.
6. When staying in hotels use the safety boxes to keep cash, jewels and documents protected.
7. Lock doors and windows in your place of lodging.
8. Keep a photocopy of all documents/passports in order to facilitate the retrieval of any lost item.
9. Don’t be a victim. Be aware of your surroundings and know WHERE you are at all times.
10. Do not wear valuable jewellery that can draw attention to you.
11. In the city carry small backpacks in front of you.
12. Stay alert if someone approaches or pushes you, or you feel that you are being followed. Notify the nearest police officer or walk into the nearest public establishment.
13. To exchange money only use banks or authorized exchange windows. You will need your passport for all bank transactions.
14. Use ATM’s that are located in public and well lit areas. Avoid help from strangers. Withdraw, count your money, and put it away before leaving.
15. If travelling by bus keep all carry-ons in your possession. Verify you have all items before departing bus.
16. In the event of an emergency always call 911 first. Ask for an English speaking operator. Identify your local police station and/or town.
17. If during your travels you feel lost or experience any difficulties you can call 800-TURISMO