The following question here was triggered by a question on Pro Webmasters for shutting down a website on Sabbath. Before asking, I would like to clarify some things beforehand: I am neither a Jew (neither ancestry nor religion) nor a Christian. I am also often very direct and focused more on a technical aspect when asking or answering, so I hope to not raise feathers.
There are several passages in the thread which are raising my eyebrows:
if it's a website that is particularly likely to attract Jews, the author would be contributing to the violation of the Sabbath by the non-observant (similar to the idea of "attractive nuisance" in U.S. law), which is not permitted.
Later again by Jeffiekins:
According to Jewish Law, it is not permitted to make it easier for another Jew to do something they're not supposed to do, regardless of whether (s)he accepts that the restriction applies to him/her. (Bold formatting by me).
As a religious Jew, though, it becomes relevant to me when I become involved personally. Halakha dictates that I cannot enable a Jew to violate halakha because it is "placing a stumbling-block. "
After reading the relevant passages of "Lifnei iver", my understanding so far is: You cannot be impartial or have a "Not my business" attitude according to halakha: If a Jew is in danger to involuntarily (!) commit a sin, it is a duty to try to prevent the sin. This can be active (shout a warning, block the way) or passive (inform e.g. gentiles about aspects of halakha so that they do not involuntarily facilitate sin). It also includes passive resistance: Do not support business which facilitates sin or give people opportunities to sin. So far nothing unusual.
The website thing is only a specific example which may be a violation or not, so for the sake of the argument we assume now we are talking about a real violation of Halakha.
The situation is as follows: In most cases a Jew is a customer and a gentile is the provider, admin and designer of the website. Other Jews have no influence on this decision and they also have no way to directly influence the website by visiting it. Setting up a website running on Sabbath is also very likely a voluntary act, especially if the customer is of Jewish ancestry and non-religious. "Attractive nuisance" refers to children which have a limited self-awareness, so it is not a proper comparison.
I really do not see how "Lifnei iver" could be applied in this case.
Essentially it is about a situation where a non-religious person of Jewish ancestry violates halakha on purpose and other Jews cannot influence his actions directly.
What are the boundaries of "Lifnei iver" in this case ?