Answered by Shaykh Faraz Rabbani
While travelling if we pass by some field and are fascinated by fruits in it and pluck without asking anybody(because there was nobody to ask) , is it stealing?
In the Name of Allah, with blessings and peace on the Messenger of Allah
Walaikum assalam wa rahmatullah,
The Messenger of Allah (peace and blessings be upon him) said, “Nothing is permitted for a Muslim from another’s property except with their willful agreement.” [Related by Ahmad and others]
The general principle is that it is not permitted to take another’s property without permission or agency. [Ibn Abidin, Radd al-Muhtar]
Permission can be explicit or effective. The general customary practice of a land or area establishes effective permission. Thus, if you are sure that the established custom of a particular place is that people don’t mind passersby picking the odd fruit from their trees, then you can do so. If you aren’t sure, it would be haram to pick it up. [ibid; Nablusi/Barkawi, Sharh al-Tariqa al-Muhammadiyya]
And Allah alone gives success.
Faraz Rabbani