In the gallery, a notice warned patrons that elements of the exhibition were unsuitable for children, "and there was no controversy here or in Chicago about the show's content," Mr. Burbank said.

Companies that store customers' private information on wireless networks will be required to install basic security measures, and public places with wi-fi hot spots must post signs warning patrons to use personal firewalls and be wary of hackers.

Theaters warned patrons of its possible nauseating effects, cautioning pregnant women in particular.

They have considered posting signs warning patrons that the F.B.I. could be snooping on their keystrokes.

The performance begins with the sound of the chimes that warn ballet and opera patrons to take their seats quickly.

His painting speaks of the same rebelliousness, with the pigment more often poured on than brushed and the sense that the artist experiences no afterthoughts (except on the checklist, where he warns prospective patrons that "prices are subject to change with notice").

Tanning salons are unregulated and unlicensed in most states, including New York, and they do not always warn patrons of the health risks involved in artificial tanning.

In Miss Tyree's case, a sign outside the 8-by-5-foot tanning room at the Jack La Lanne club on 86th Street warned patrons that they should not tan longer than two minutes, she said.

Then, from a disembodied voice, came another announcement: "We must warn patrons of a nervous disposition that platform boots and white Spandex are featured in this production."