Here's an interesting couple of paragraphs about phone service in Philadelphia during the second wave of the 1918 influenza. From
So many phone workers were out sick that calls were limited to emergencies only. Bell Telephone took out ads in the local papers to announce that no calls would be accepted "other than absolutely necessary calls compelled by the epidemic or by war necessity." One such ad stated:
"Telephone Service Faces a Crisis--The situation is one which the public must meet squarely--800 operators--27% of our force--are now absent due to the influenza. It is every person's duty to the community to cut out every call that is not absolutely necessary that the essential needs of the government, doctors, and nurses may be cared for."
Crosby tells us that Dr. Krusen empowered the phone company to cut service to any customers that made unnecessary calls; about 1,000 people were disconnected for violating that rule.