If a person changes time zones while going on a vacation, do they have an obligation to alert others to this effect? By using social media and other types of online sites (like Mi Yodeya), not telling people in advance might create the impression that they are doing these things on Shabbat.
Is this a case of mar'it ayin: leading people to believe that this person is doing something wrong?
Is it a case of lifnei 'iver: causing people to think that using computers on Shabbat is okay?
And if it is a problem, what is the minimum effort that a person needs to go to in order to inform others? Does a person need to add something to their public profile, for example? Is it necessary for them to change their status on Facebook? Is this issue discussed in any contemporary literature?