Some time ago in the Hebrides and the Highlands of Scotland something invasive happened. It is called the Clearances. Rich people who owned the fields of the farmers wanted the fields cleared of farmers. The crofters as they are known. In the process people even invented a racist argument to clear the Highlands of the so called inferior Celtic people.
A real invasion with help of army, navy of thousands of sheep did do the job. The farmers had to move from their farms and clear their fields. They had to move to other countries to survive. The house in the picture above is part of a deserted village on Lewis and Harris (Outer Hebrides)
Invasive is not only a biological word used for some plants, but it is a word used in wars and with force of weapons. And it is a word used for cancer cells invading in tissue.
Invasive conduct in a course happens almost unknown. People enter the room and space and ask for attention and answers and reactions. Just that, no harm meant. But it is invasive conduct and other participants have to give room and space or disappear or fight back.
The members of discussion groups do know these few who always are first to answer questions and who talk more than other members of the group.