Instead, trademark law protects brand names, logos, symbols, designs and other optional elements of apparel and accessories, and trade dress law protects the design, packaging or appearance of apparel and accessories, solely to the extent they identify the source and origin of such products.

FORBES: Protecting Fashion Designs

To be clear, elements that do not identify source and origin of apparel and accessories do not qualify for protection under the US Trademark Act.

FORBES: Protecting Fashion Designs

As Apple is using the reply-to address of a message's User Data Header to identify the origin rather than the raw source, receiving iPhone owners risk being fooled by a phishing attack (or just a dishonest acquaintance) that poses as a contact or a company.

ENGADGET: iPhone reportedly vulnerable to text message spoofing flaw