Parks Canada is responsible to make sure they are maintained. There is a program, and they certainly are replaced when it's identified. If the text on the plaque is more than 25 years old, it will be re-examined in terms of the most recent historiography because, of course, one has a new appreciation of a number of things as history is written over the years. Therefore, we occasionally will revise a text when that occurs.
There have been thefts of plaques, especially as metal prices have gone up at certain points, and occasional vandalism, but Parks Canada is pretty good at trying to identify and have a program for replacement.