Third-party uses permitted by the owner of a mark may also be probative of the abandonment of a mark by the owner. A mark is abandoned when any course of conduct of the owner, including acts of omission as well as commission, causes the mark to lose its significance as an indication of origin. See 15 U.S.C. § 1127(b). Failing to take action against an infringer has been held to be such an “act of omission.” Sweetheart Plastics, 743 F.2d at 1047; Wallpaper Mfgs. Ltd. v. Crown Wallcovering Corp., 680 F.2d 755, 766 (C.C.P.A.1982). Once a mark has been held abandoned, it is free for all to use and falls into the public domain. It may be seized by another, and the person doing so gains rights against the whole world. 15 U.S.C. § 1115. However, as the court in Sweetheart Plastics emphasized, “[t]he issue is hardly ever ‘abandonment,’ because that requires proof that the mark has lost all significance as an indication of origin” and is “completely without signs of life.” 743 F.2d at 1047–48.
So long as there is no abandonment or estoppel by acquiescence, a trademark owner’s tolerance of third-party uses of his marks will not bar enforcement of his rights against an infringing user. It may, however, bear on the issue of the strength of his mark. The damage that third-party users of a mark can cause an owner who seeks to enforce his mark is the weakening of the mark’s strength. Failure to take reasonable steps to prevent third-party uses of the mark may weaken a mark to the point where it is entitled to only a narrow scope of enforcement, and ultimately the question may become one of abandonment. However, where the owner of the mark has been reasonably diligent in protecting his rights, even though infringements exist, no intent to abandon will be inferred. J. Thomas McCarthy, Trademarks and Unfair Competition, § 17:5 (2d Ed.1984 & Supp.1987).
In this case Quality International does not contend that McDonald’s has abandoned its family of marks or that McDonald’s has acquiesced in Quality International’s use of McSleep Inn. The Court likewise reaches those same conclusions based on the evidence presented. McDonald’s gave no assurances, expressly or impliedly, to Quality International that it could use McSleep Inn, and McDonald’s did not delay in pursuing enforcement of its marks. The evidence of third-party uses introduced by Quality Inns therefore is probative only of the strength and scope of McDonald’s family of marks. These uses will not preclude the enforcement of those marks against Quality International.
The Court can point to no evidence that public awareness of McDonald’s family of marks and their attribution of source to McDonald’s has been lessened by the third-party uses. The more important question, and probably the only relevant one, is whether third-party uses are so prevalent that the public would not likely confuse McSleep Inn with McDonald’s. The Court found no evidence to suggest impact by third-party uses on this question of confusion. Although the question is more fully encompassed in the answer to the issue whether McSleep Inn is likely to cause confusion, which is discussed below, suffice it to conclude at this point that third-party uses do not preclude McDonald’s enforcement of its family of marks.
IX. GENERIC DEFENSE
Both Mr. Hazard, Quality International’s CEO, and Mr. Mosser, its vice president in charge of franchising, urged at trial that “Mc” has become a generic prefix meaning thrifty, consistent, and perhaps convenient. They urge that the notion of thriftiness comes from the association with the Scots and the perception that the Scots are thrifty. The Court was directed to the writings of H.L. Mencken, the famous Baltimore journalist and writer, who said:
Nearly all the English words and phrases based on Scotch embody references to the traditional penuriousness of the Scots, for example Scotch coffee, hot water flavored with burnt biscuit; to play the Scotch organ, to put money in a cash register; Scotch pint, a two-quart bottle; Scotch sixpence, a threepence; and the Scotchman’s cinema, Piccadilly
