Accidents and robberies do happen in Thailand and the health risks are greater than in Europe. Bank transfers can take time and if you miss your return flight, you may have to purchase another ticket to get home. DON'T carry anything through customs for someone else unless you know exactly what it contains.
Condoms made by recognised multi-national companies are widely available locally from pharmacies.
Thailand recognises such acts as rape. DON'T let them out of your sight or leave them unattended unless you are sure that they are safe. DO report any loss immediately to the nearest tourist police. It is not illegal to sell inferior quality gems at inflated prices. You might return home to find that your gems are worth less than you paid for them .