Appreciate the response; I'm a developer as well so I understand the inherent risks.

So, without going into too much detail and taking away from the tremendous amount of work that creating an app like this is, I'll say that it is important because most users will reuse a single password across all of their accounts online.

So, if their database was by any means leaked out, there's a nice little list of email addresses and password combinations that will work for a majority of other sites - including email accounts, private forums where sensitive data may exist, maybe some online banking apps, etc..

Also, if there's any possibility of untrusted user input being interpreted as code, well, you're doing something wrong.

Anyways - back to the topic at hand. Nesting items inside of others seems like it would introduce a fair amount of complexity both in terms of the UI as well as on the back end, but it'd be worth it if people would use it. I know I would, but whenever I browse other people's gear lists (typically spreadsheets), they're always just flat lists. However, that may just be because the spreadsheet format doesn't really make it easy to do stuff like that. Best to keep it simple in that case.