The arrest of three Westerners, two journalists among them, on a charge of murder is a reminder to be careful about getting involved in political issues when traveling in foreign lands. The trio had been meeting with Hmong rebels in an effort to shed light on their cause, which has attracted scant attention in Western media even if it has been going on since 1975. Journalism organizations believe the murder charges are fabricated, but the two European journalists and their Hmong-American guide remain in custody without being allowed visitors from their embassies.