Ethical and Legal Considerations

It does not hurt to reach out and ask if other hosts you notice should be included, but, again, make sure this is in writing and not just given on a phone call.
Document, document, document. When in doubt, document and overcommunicate.\
If you participate, even if your intentions are good, you can still be liable and get into legal and even criminal trouble.
When working for any company, make sure that you have a copy of the signed scope of work/contract and a formal document listing the scope of testing (URLs, individual IP addresses, CIDR network ranges, wireless SSIDs, facilities for a physical assessment, or lists of email or phone numbers for social engineering engagements), also signed by the client.
When in doubt, request additional approvals and documentation before beginning any testing.
While performing testing, stay within the scope of testing.

if in doubt, reach out

Penetration Tester Path Syllabus