FlyerTalk Evangelist and Ambassador: The British Airways Club
Join Date: Jun 2008
Location: Somewhere between 0 and 13,000 metres high
Programs: AF/KL Life Plat, BA GGL+GfL, ALL Diam, Hilton Diam, Marriott Gold, blablablah, etc
Posts: 33,190
If you feel that you might need not to fly, you are far better off not checking in until you are sure that you will make the flight. Presumably, by the time you are on your way to the airport you will be reassured that you feel comfortable going. You can then check in online or at the airport till the last minute.
Checking in means that you would not be able to cancel the ticket yourself directly online/on your phone and thus adds unnecessary risk that you might miss the cut off point and be considered a no show.