Newbie: basic Q's about 'registration' and 'iOS dev'

Hi everyone, basic Q's getting my feet wet:

- If stencyl runs locally why does it ask for login/registration to fun FREE version?
- When start creating your game you start by choosing screen size.  Can you "convert" (or re-do) for mobile a game that was originally created on desktop size? or is this something that has to be decide before starting?

- Stencyl can connect to StencylForge which requires registration to use.
- You can change the game size at a later date easily, you just have to pick it when starting off as you need it to test a game.

Great. Thank you.