Client Offline

Hello Experts,

I need to make some client offline as there is some activity. So few Queries.

1:- Suppose activty starts at 11 Pm and backups starts at 10 PM and if i put this client offline from 11 PM till activity completes. What will happen to backup

     Would it run or get failed with 1000 error code at 11 PM?

2:- Is there any way i put client offline just before the activity i.e 11 PM and as soon as activity start backups fails before this activity and become offline? So that if some backups are running some get succussfull.

Thanks,