Is it permissible to take something based on the strong presumption that its owner would willingly allow it?

It is permissible to take something when one has a strong presumption that its owner would willingly consent to it, such as eating and drinking from what a colleague possesses. This is based on the Almighty’s saying: "There is no blame upon the blind, nor any blame upon the lame, nor any blame upon the ill, nor upon yourselves for eating from your houses... or your friend's." Customary permission is akin to explicit permission. Thus, if the owner's consent is known through custom, then their permission is granted. As for the matter of tips and gifts for workers, that requires elaboration.