Marsha and Marion created the following material for one of our training events to introduce/remind participants of some of the most important rules for orienteering events. It has been edited slightly:
First and foremost, the sport is grounded in participant integrity. For the most part there is no marshall on the map ensuring you are complying with the rules. They only have marshalls on major international events, and you will be disqualified if they catch you flouting the rules.
Out-of-bounds areas on a map:
Areas marked out-of-bounds or uncrossable on a map (e.g. olive green areas, purple or black cross-hatched areas, etc.) are ALWAYS out of bounds for the event, even if the reason for mapping it as out-of-bounds is not obvious to the participant.
On a sprint map (most city maps) a fence shown with the double tag lines is uncrossable (see picture below), no matter if you think you could climb over it. An easily crossable low fence could be mapped as crossable (a thinner line often with single tags as in the picture below) or uncrossable (a thicker black line often with double tags on the line) depending on whether or not the mapper determined that it is appropriate to allow crossing of the fence. This is to ensure safety and fairness for all participants regardless of climbing ability or sometimes to avoid damaging the property.
In general, anything drawn with the heavy black line is uncrossable, such as a wall.
If the control is shown as the inside corner of an uncrossable fence, then you have to go to the inside corner so you could physically touch it. Reaching over or through an uncrossable boundary is against the rules.
Buildings are out-of-bounds unless they are shown as the light grey of a canopy when you can run through them (e.g. part of a building that overhangs).
Choosing a route:
It is important to check the control description so that you can plan your route for where the control is (inside an uncrossable fence, for example, means you should be looking for how to get into the fenced area).
In planning a good sprint course, the obvious route isn't always the best one.