Is a booking website that deals with hotels on a commission basis sinful if a tourist books through it and then drinks alcohol or commits a sin? Does the same ruling apply to advertising websites that feature companies and stores whose owners commit sins? And is someone who works in satellite dish installation sinful for installing it in general, even if it doesn't bring in forbidden channels?

In such cases, the individual should base their decision on the prevalence of their strong presumption. Dealing with a tourist to book a hotel is permissible unless there is a strong presumption that they intend to commit something unlawful. If such a strong presumption prevails, then booking for them is not permissible, lest one becomes an aid to sin. Similarly, regarding the installation of a satellite dish, if there is a strong presumption that its owner intends to commit something unlawful, then assisting them is not permissible; otherwise, there is no objection. As for advertising for shops and companies, if the advertisement itself contains something unlawful, then it is not permissible. If it does not contain such, then one should consider the activity of the advertised entity. If its activity is predominantly unlawful, then advertising for it is not permissible; otherwise, there is no objection.