Long term viability of Perch site

Our site is being Archived as an historically important entity by several national Archives. The idea is that the material we research and publish will be available as a research resource to future generations. There could be several instances of our site across the world. These will not be online so long as our main site is running, but would be made available after this ceases.

Almost all our content is created and published using Perch and we would like to understand if it will still be readable in, say 100 years, long after we've all written our last line of code. The area of concern is the licence checking you do. Does the check occur if the site is in read-only mode? i.e. there is no use being made of the creation side of Perch? Will there be a problem if there are several instance of our site in use, all of them read-only?