Based on the pasuk "Lifnei Iver Lo TIten Michshol" - "Before a blind person one should not place a stumbling block," chazal understand that there is a prohibition to cause another Jew to violate a prohibition of the Torah. 
- For example, one who borrows and pays back with interest, besides for other transgressions of interest, the borrower is in violation of Lifnei Iver. 
- Regarding leaving a commercial website or a vending machine on during Shabbat in a place where non-religious Jews may use it, see Minchat Yitzchak 5:14, Shevet HaLevi 8:40(1), 10:57, Chelket Yacov 70, VeYan Shmuel 8:11, Rabbi Shmuel Pinchasi (VeDaber Davar 6:12, pg 148), Maareh habezek 5:37, and Darkei David 2:38.
- Right before Shabbat it is forbidden to get in a taxi if the driver is Jewish if there’s not enough time for him to get home before Shabbat after he drops you off.
- There are poskim who are lenient regarding the rabbinic form of lifnei iver for a non-religious Jew specifically if he is going to violate the prohibition intentionally. This does not apply to the Biblical cases of lifnei iver.
- Vayikra 19:14
- Rambam Sefer HaMitzvot (Lavin 299)
- Bava Metsia 75b
- Or Letzion (v. 2 p. 153 16:7)
- Dagul Mirvava to Shach YD 151:6
- Shach 159:3 applies lifnei iver to giving interest to a mumar.