It doesn't need to access service mode to get this data
There's a whole load of RS-232 commands that can be sent to the TV without needing service mode including the ISFccc interface. You can also control the TV as if you were using the remote control. i.e. call up the usual onscreen menus and change channel or volume etc etc. The info to do all this is on the Pioneer website.
Service mode access requires a separate command and this unlocks loads more commands but no one really needs access to these.
The only possible exception is the grey sidemask control for 4:3 content. In order to change these to black you need to access service mode first.
I haven't released any freebie programs to allow sidebar adjustment for that very reason. i.e. the TV has to be put in service mode first.
I'm not convinced the warranty would be automatically invalidated anyway and I would be more concerned that people would want to explore service mode and end up adjusting stuff that should be left alone.