Could be a wordplay due to the fact "invigilation" can be translated to and from the Polish word with a _very_ heavy and long connotations to the USSR state surveillance, oppression and abuse.
Surveillance would be a more "modern" (even if more natural or seemingly correct word), without this sort of the implied baggage.
Surveillance would be a more "modern" (even if more natural or seemingly correct word), without this sort of the implied baggage.