With the sheepish ones just letting them know you won't do it. That it crosses the bright line can make them back off some of the time.
This can be very scary and if you are thinking "but I could be fired" I understand that. Ask for help. Talk about it outside of work or with people you trust. Don't go looking for an excuse to comply and not feel bad about it. If you do you should feel bad.
Find a way to NOT do it instead.