Allow people to search for existing users
I know my friend has a splitwise account, but since I don't have his email I can't add him to my group. You should be able to search for someone's name if they have an existing splitwise account and be able to add them from there. It's extremely frustrating to have someone who owes me money tell me they're on splitwise and then have them stop responding when I ask them what email they used.

Very sorry for the trouble! Unfortunately we don’t have plans to allow you to search for users by name :(
Most names on Splitwise are not unique – for example, there are hundreds of Splitwise users named “Scott”, and many do not include a last name. There are also security and abuse concerns, as search-by-name could be used to easily add debts with people who you do not actually know.
My apologies for the inconvenience! I realize this is a pain, but because Splitwise works in a very open manner (e.g. you don’t have to manually approve every friend request you receive), we require an email address or phone number to help verify that you know the other person.