nah, the idea is that when real lightning is approaching you get a warning. But when is it real? if it is very remote, it might easily take 5 or 10 minutes between strikes. So if the first strike happens at say 11.00, nothing would be reported, if nothing else happens in the next 15 minutes, this would be considered a false detection, if however at 11.03 another strike is detected, both strikes would show up in the graph and a notification is send to the user (if enabled). That would cause a 3 minute delay, but only on the first strike, the rest are all detected in real time (until nothing happens in 15 minutes). if the second strike would happen at 11.01 there would be only 1 minute delay, but if the second strike happens at 11.14 you would get a 14 minute delay (I would consider both strikes real lightning if they happen within 15 minutes of eachother). This 14 minute delay is unfortunate, but for severe storms lightning is much faster and the delay is only minimal. Adding this as an option, so users without false strikes are not effected seems a no brainer to me, but apparently other people think differently (they prefer real time, but inaccurate weather in a super simple ui, without options)
so to answer to you remark. this 15 minute window is only useful if there aren’t many false strikes at all. A second false strike in 15 minutes would be considered real lightning.