R. Gil Student writes:
In summary, according to the Sha’ar Ha-Melekh, you may not assist someone to do something you consider forbidden even if he follows a different legitimate view. According to the Mabit, Kesav Sofer and R. Auerbach, you need not be concerned about lifnei iveir if someone follows a legitimate lenient view.
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From what we have discussed, it seems that during the week you are allowed to ask someone to do something that your rabbi considers forbidden but his rabbi considers permissible. R. Shlomo Zalman Auerbach and others rule that lifnei iveir does not apply and most authorities follow Rav Sama, that ein shali’ach li-dvar aveirah still applies. Halakhic pluralism means accepting that someone else may legitimately follow different religious practices than you.
