The only things that should go into a toilet are the THREE Ps:
All else causes problems and increased costs to repair and maintain our Wastewater (Sewage) collection and treatment system. This impacts YOUR utility user fees and property taxes.
Causing a back-up can affect a whole block. Just talk to someone who has experienced a raw sewage back-up in their residence and appreciate that it is worth being more careful in the use of the Town's sewer system.
Sewer Line Maintenance - it's important
The Town is not typically responsible for what happens to your sewer line between your home and the sewer main in the street. Property owners needs to take special care of their line and investigate backflow problems/ deficiencies, particularly if it is an older line:
If you are concerned about backflow, it important that your sewer line has:
A backflow prevention valve and clean-out access in the basement of the home;
An unobstructed vent stack (check regularly for blockages like bird's nests);
A functioning basement sump pump - they're not just for rainwater.