We have a mishna berrua and shulchan aruch shiur and the following question came up:
Siman 405: Techumim for Shabbos.
If a married man took a walk into the woods on a Fri. night ( ie. “Hitbodidus”, or simply to walk off anger ), and when he realized how far he had walked he was outside the Techum for My City (acc. to all opinions). Halachally he is not allowed to return back home (Derabunun). But if he does not, he will cause his family to worry, which will lead
to Chillul Shabbos (Deoraisa ) for his search on Shabbos.
Is he allowed to return home to avoid this ?
I think this related to Tosfos on Shabbos 4A, which deals when a person is allowed to Sin to prevent a fellow Jew from sinning worse. As he would be the source for others sinning, should he be allowed to sin a smaller sin, as to prevent others from doing a bigger sin?
Answer:
Under the circumstances, the person should walk back home.
The reason for this is based on Shabbos 4a and on Eruvin 32 (and Tosafos in Shabbos), where we find that although it might be forbidden for a person to transgress a minor (rabbinic) offense to save another from a major offense, this is not the case where the person in question is causing the other person to sin.
In the case of the question, not coming home will be causing other people to violate Shabbos, and therefore to prevent this from happening it is permitted (and mandatory) to come home, even if this involves a techumin prohibition.
Note that another reason why it might be permitted is that not coming home might cause many people to violate Shabbos, and this is therefore a matter of many, for which Tosafos writes a rabbinic prohibition can be transgressed.
Best wishes.
