Hermione hadn't made up her mind one way or the other whether or not she was going to put herself and her son in danger to work with the Resistance. Sure, she might have said she would consider it to get Ginny Weasley to teach her how to cloak her magic, but not once did she make a single promise. Knowing how to perform magic without Antonin being able to pick up the trace was her ticket to actual freedom. Maybe she could disapparate across the Channel or imperio some ship captain to take her to another continent. Pretending to be a spy, at least in the beginning, could get her what she wanted. After all, she wasn't a selfless being any longer. If there wasn't something tangible for her to gain, she wasn't going to do it.