@FlaPalmLover if it's easy to keep water out then it's a good idea. Conventional wisdom also says to avoid overhead sprinklers. Yet every single palm nursery on the planet uses big overhead sprinklers, at least until 10g or bigger sizes. They switch to drip lines with emitters or bubblers on 10 to 100g pots. If overhead sprinkling was a serious risk then they wouldn't do it...they'd be risking their livelihood on it. For sure I wouldn't intentionally spray water in the crown, but I doubt a bit of rain is a serious risk.
Other people here suggested Daconil in the crown, partially because it stays tacky when it dries. So the mixture *might* stick around in the crown even with some rain. Honestly, as long as torrential rain doesn't wash into the crown, many (or most?) would stay in place. And a systemic (like Banrot or Aliette or others) is great when absorbed. Systemics may be slower though, I read a study somewhere that it could take 1 to 2 weeks to get from the soil to the crown. So I like the idea of the 2 step treatment. I did a soil drench of Banrot + Aliette on a few key palms like my mutant Elaeis, a couple big Arenga Pinnata, and several Attalea Brejinhoensis. Those were all seriously burnt and the frond stems were at least partially burnt towards the crown. So I figure both is a good choice.
@junglejim welcome to PalmTalk! I had a couple of 1-2 year old Pandanus Utilis (I think), but both died after 27-30F frosts. They defoliated and started to regrow, but then caught a crown rot and died. So a good crown treatment (Daconil, hydrogen peroxide, Mancozeb, any copper-based, etc) and a systemic (Banrot, Aliette, others) is a good choice.