Everybody seems to be assuming that she must be guilty of some criminal activity.

Don't know what the law says in the UK but she would be guilty of criminal activity in the US.

In American law, providing material support for terrorism is a crime prohibited by the USA PATRIOT Act and codified in title 18 of the United States Code, sections 2339A and 2339B. It applies primarily to groups designated as terrorists by the State Department. The four types of support described are "training," "expert advice or assistance," "service," and "personnel."