Thank you... If there's any bonding between the to of you, yes there could be problems. A 'TOO, bonds with one bird or person, sporadic visits, bringing hims food or gifts, he'll relate that and look forward to your visits...We don't know how our birds measure time, we do know they don't forget. Only a suggestion, take the toys, food, etc, give it to the owner to give to his 'TOO, with you out of sight so he won't relate to you, maybe the owner will get the hint, try to educate him, you would more or less,"look in from the outside", A 'TOO, is one of the most human connected birds there is...If things didn't work out, it could lead to plucking etc..
Jayd