SharkNinja, Dyson end legal battle over advertising claims

In court documents, Dyson acknowledged that its claim became false once Lift-Away came out, but insisted it took prompt steps to eliminate the "twice the suction" advertising from the market, including spending nearly $1 million to replace packaging.

A footnote said the claim referred to only one Dyson vacuum — the DC40 — but Dyson argued in court filings that the footnote was so small and inconspicuous that most consumers would not have noticed it and assumed the claim compared it to every full-size Dyson upright.

Stacey Dogan, a Boston University law professor who specializes in intellectual property and competition law, said these kinds of cases can become emotional for two companies who take brand loyalty seriously.