Now that Animal Crossing Nook Miles Ticket most people have experienced all four seasons, and the two hemispheres have been in various seasons, I really don't think a spoiler tag should be crucial for general content that occurs in various months due to TT.
But, I would support a spoiler tag for some events/items (e.g., toy day, festivale) and particularly for items which can only be collected from completing that event (like the festivale float) or which may only be obtained via hacking (as opposed to an item collected through TT and traded into a player who does not TT), maybe until the event is unlocked/has started in the past period zone/items are added into the match and considered"tradeable" without hacking.
ETA: Personally, screenshots of players using hacked items bothers me , not because they"spoil" (especially if they're at the trailer), but since the comment threads end up being filled with folks asking how/where to acquire the things when they aren't readily available to the majority of players. Once they're officially accessible whether in TT or actual time, fine. Either a dedicated day of this week for posting them (or even have them allowed on the evenings ) or a megathread
Images taken of the console display are fine provided that the picture is discernible. There's no point posting photos with this much glare which I can not see what is happening. HQ images are easy to get to a phone with the newest update. (I saw the article with the change in the microwave. It was insane)
photos of clothing/merch could be kind of repetitive. Sharing the announcement of this colour pop collab made buy bells for animal crossing new horizons sense. Everyone posting a photograph of the exact same palette or box when it arrives at the mail is tedious.