That seems fairly disturbing; couldn't you just say "you must follow @startuppack to be eligible"? Then you wouldn't need ongoing write permission to the user's Twitter account.

Disturbing is an exaggeration, but it would certainly be just as easy to get read only rights (just to confirm it's you) and also check to see if they're following.

I have rejected a large number of apps because they want write access to my twitter account for no discernible reason.

The reason posted above makes sense but it would never have occurred to me so I would have rejected this out of hand.

Companies should say why they need write access with clear reasoning if they want me to use them.

Dude, don't lower the standards.