How to sort civimobile event participant check-in list?
I think it makes sense as the default behaviour. Can you go to the github project and add an issue there to talk directly with the developers and consider proposing that as a PR? https://github.com/webaccess/com.webaccessglobal.module.civimobile

The line you'll need to change is the api call, and add a "option.sort"="whatever is the field for the participant name" param (use the api explorer to find out the exact syntax and name of the field name)

https://github.com/webaccess/com.webaccessglobal.module.civimobile/blob/master/code/civimobile.participant_checkin.html#L35