[Ask HN] How much of competitive intelligence gathering is too much?

I am working on a new app, which has similar existing apps in the market. I registered and used these apps to get an idea about the features of the apps. (For each of them, I registered multiple users, tested the functionality heavily etc). Its trivial to prove that the user is me, as I registered at all places with my primary email address, or variants.

SO what am I wondering if there can be clause in the various EULAs I checkboxed, which says that you can not use our software to create a competitive software etc, and can it be enforceable?