It's distressingly cute for a tentacle book, but I agree with telamon up there — adding habitual child rape to the list of Presea's canonical brutalities is maybe a bit much as a throwaway setup line. (I mean, we all agree she didn't learn that from Lindy, right?).
However jokingly, it does bring up a note of concern about Nanoha and Fate's relationship — the worry that Fate is a little too eager to subsume herself into whatever Nanoha wants. I think that StrikerS and subsequent works manage to avoid that by having Fate have her own life and career (which is certainly inspired by Nanoha but not completely stuck to her), but it is a concern.