Guild Member Activity
Desktop: Open Guild profile, check members
Mobile: You don’t
Friends Activity
Open Social Bar (Assuming you’ve unlocked it), click on / hover over any player in the Friends Tab.
Event History
Enter Town Hall
Go into Event History
Filter by Social Interactions and [relation with player]
Aid everyone that is filtered
Now go to your Social Bar and select whatever you filtered for when aiding in Event History. Anyone that is still aidable hasn’t aided in the last 5 days.
Not foolproof, but if they aid they’re logging in