Back in the days of Malawi/Mexico scandal that we look back at, people have to remember that there was no internet and you couldn't find out what witnesses in other countries were doing or allowed to do.
Malawi witnesses understood that being neutral and honest meant not buying a party card which to them meant they would prove disloyal to Jehovah and his organization. You didn't see Watchtower have articles stating that Mexican witnesses could bribe military officials to obtain a military card nor did watchtower print stories that they weren't a religious organization in Mexico because it benefited them more to be known as a cultural organization. Since there were stories (I don't remember if there were printed articles) about Malawi witnesses suffering for the party card may be why Mexican witnesses were having troubled conscience because deep inside they knew bribing was illegal even though culturally acceptable and that's why they wrote to society inquiring about that practice.
GB could have advised Malawi witnesses that it was up to their conscience but GB chose not to. While it was up to American witnesses' conscience to sign the oath of allegiance when applying for passports, it was up to Mexican witnesses to bribe officials to get a military card. Jwfacts is right about stating the the blood guilt falls on the hands of GB members since they were the ones that allowed Malawi witness persecution while due to double standards and hypocrisy!
What holds witnesses back is not physical force but their belief system in following what wts tells them to which often equals to being held back physically in fear of dying at Armageddon or displeasing God and that's also the reason why majority of witnesses won't talk to df/da or even inactive witnesses because they follow the GB leaders' "command."