Well, If Naru does learn of it. Obviously she's probably going to think it's a scam too. But if the proof comes up then yea, I can see her being horrified and everything. And despite thoughts of the contrary, she is a good person. So she probably will try and reject Keitaro to protect him. The problem with this is, well, Keitaro is kind of hard headed and may still pursue her anyway. On the other hand, with the reality slaps that Tomoko has been handing Keitaro. Maybe he'll be more cautious this time?
It feels like this seems like the perfect time for a breather episode where people begin to re-evaluate their way of doing things, at least for Keitaro and Naru. Not sure about Motoko and the others though. Especially since Tomoko inadvertently interrupted Motoko's character development arc where she grows as a person and solidifies her feelings for Keitaro. Whoops?