Hi Edouard.
By your questions it sounds like I might be misunderstanding something. So please allow me to explain the scenario where my suggestion works for me. Hopefully that will help pinpoint for you anything I might be misunderstanding.
Whenever I clean, lube or adjust anything on my VP-2, I disconnect the rain and wind sensors. In this way, for one example, if the tipping bucket tips back and forth, it won't register as any rain. So there's no data errors at all, and none for me to "ignore".
The short time it takes me for maintenance stuff - and thus the short time the sensors are disconnected - does not have a mathematically significant effect on any of the running averages.
If I am missing something, please let me know. But it's been my experience that, since I can in fact disconnect these sensors during maintenance, it's a foolproof way to go about it.