"Even if their eyes start to feel uncomfortable or they start to get a headache, they're less likely to tell their parents, because they don't want to have the game or the computer or whatever taken away."
VOA: special.2011.08.01
And, while physical activity typically aggravates migraine pain, it doesn't make tension headache pain worse.
It's an odd predicament, to say the least, but if you're familiar with the kind of off-field trouble that professional athletes can get into, an imaginary girlfriend doesn't sound like much of a headache for human resources.