Most won't. If you attend Grand Prix, Nationial or World's matches they stop for lightening and major flooding, nothing else. I use these opportunities to test not only my gun/scope combo but also my soft case (+5lb in the rain) but also any rain gear I think will be beneficial.
I need a good pair of rain pants. My snow pants did not work in the rain. The match was good practice for me. My LGU rifle and Sightron scope did it’s job. Need more work on wind doping skills in hurricane conditions. Hope England is not as bad this match. We had to remove the tent canopies because the wind gusts were too strong.
This may be a stupid question, but if one dries their rifles off good, and wipes them down with something like balistol afterwards, why is it not a good thing to shoot them in the rain?
Some people do not like getting their prized possessions wet or dirty. They keep them in safes and don't use them outdoors. Nothing wrong with that.
When you are a serious competitor like in field target, you need to test your equipment (rain gear especially) and train in adverse weather conditions.
Most people won't do that and it's ok. It's not for everyone.