Can a neighbors remote affect your TV volume?

if they are in your house and have got a programmed international remote pointing at your tv then no - basically, a sort of laser comes out of the top and goes to your tv to change channel and stuff. If they're in their house next door then it'd be impossible because of walls. BUT if they were across the road from you with their Windows open WITH an intl. remote programmed for your tv and your window was open and they could see the tv; THEN yes. but unlikely

Another answer, today many remotes can be switched to the Radio Frequency mode from the Infrared mode which would allow a remote in another house close by to control your TV.