Historical clue formulations

• Sound the alarm — 2025-10-24
• Alert — 2025-02-26
• What flashers do — 2024-10-12
• Caution — 2020-11-26
• Caution — 2019-06-23
• Put on guard — 2018-03-27
• Tip off — 2017-10-22
• Not punish just yet — 2017-08-24
• Caution — 2017-07-28
• Give a heads-up — 2016-10-16
• Alert — 2016-06-27
• Yellow-card, e.g. — 2016-01-14
• Say "It's a trap!," say — 2015-05-26
• Give a heads-up — 2014-12-23
• Tip off — 2013-11-28
• Show a yellow card, e.g. — 2010-10-02
• Premonish — 2009-08-21
• Serve notice — 2009-05-31
• Alert to danger — 2009-03-02
• Give a heads-up — 2008-06-24
• Give an alert — 2007-10-29
• Tip off — 2003-02-06
• Tip off — 2002-12-29
• Put on notice — 2002-03-06
• Raise a red flag — 2001-07-03
• Tip off — 1999-11-26
• Caution — 1998-08-18
• Alert — 1997-05-27
• Alert — 1996-12-15
• Counsel, perhaps — 1994-04-23
• Alert — 1994-01-18