I generally don't take my reptiles out with me. Sometimes if its really sunny and hot out Ill put a bluey or my beardie on my shoulder and walk around my block but thats the extent of it. If I have to transport them anywhere I use a kritter keeper/condo. I honestly have never had an issue with someone asking to pet/touch my reptiles or even my dogs for that matter. That being said I don't think it would be out of line or rude to just firmly say "please don't touch my (insert animal type here)l" and if they keep on then well I would have a few choice words for said person. Maybe I just don't look friendly or approachable hahaha.