I'd like the shifters to shift into high gear if I forget my phone. There are 2 really good justifications for this feature:

1.) I never want to ride without my phone.
2.) An attempt to steal the bike would be much harder to get away quickly.

If the app/shifter had an option to shift into high gear when the phone isn't present, it would act as a reminder to get my phone.

It would also make it much harder to steal the bike (lock the bike into high gear until the phone is nearby).