The product might be designed in a way that assumes that HTTP will be used, e.g., by excluding considerations of encrypted communications between client and server.

Product requirements might not include encrypted communications, which could make it easier for designers and developers to choose HTTP.

Developers might choose to use unencrypted protocols such as HTTP because they would not require development of additional mechanisms to support encryption, e.g., key or certificate management.

When generating content that references web sites such as email messages, ensure that the https:// prefix is included. If a domain name is presented without such a prefix, then clients might automatically treat the link as if it had an "http" prefix. For example, referencing a domain like "mysite.example.com" could cause it to be treated like "http://mysite.example.com", thereby sending unencrypted HTTP requests.

Designers might assume that the responsibility for encrypted communications might belong to operators and/or network administrators.