A Travel for the Purposes of Committing a Sin

Q 675: If one knows that they will be engaged in sinful and ḥarām conduct during the journey they are about to make, will their prayer be full or shortened?
A: If their journey is not for the sake of neglecting an obligatory act or committing ḥarām, their rule will be that of normal travelers, namely, shortened prayer.
 
Q 676: If someone travels without the intent to commit a sinful act, but on the way he pursues his journey for a sinful purpose, is it obligatory for him to shorten the prayers? Are the shortened prayers he performed on the way correct?
A: It is obligatory for him to perform prayer in full from the time he intends to continue his travel for the sake of a sinful act and to repeat in full the prayers shortened he performed after continuing the journey for a sinful purpose.
 
Q 677: What is the rule that applies to a picnic made for pleasure, or a journey for purchasing the necessities of life, supposing that one will have no access during the journey to a place for praying or carrying out its preliminaries?
A: If he knows that he will have to forsake a prayer obligation during the journey, it is a caution to refrain from such a trip unless that results in harm or causes an unbearable hardship. Anyhow, it is impermissible to neglect one’s prayer for any reason.