From my recent plays of Mario Parties 2 and 3 (Including story mode playthroughs), I have seen some pretty foolish things from the AI. Fortunately it helped me get All S ranks with some characters easier at least. In Mario Party 3 I've witnessed computers have more than enough coins to purchase a star, roll a number where they can reach it on their turn, they come to a split in the road and then go the opposite path of the star space. Take Chill Waters for example, the star space can appear a few spaces below Boo near a split, I've seen a computer opponent
avoid that star and Boo by going the other way when nothing could have stopped them otherwise.
I've also had opponents choose to land on the space in front of me in Duel mode and then be finished by my partner in the front. To be fair, they had 1 heart piece remaining and no partners, perhaps they "give up" in really bad situations? They could of went the other way instead.
I noticed Luigi always seems to ignore Baby Bowser's items in favor of Skeleton Keys. Including Boo Bells. Doesn't seem to be the case with Toad's items though for some reason.
The best I can recall is Daisy using a Cellular Shopper to buy a Cellular Shopper in Mario Party 3. Wasting 5 coins. I've seen it happen on more than one occasion. I've also seen the AI buy a Skeleton Key and then throw it away the next turn for seemingly no reason.
I've seen an AI use a cellular shopper and then say no to the shop. What a dumbass. I also saw Peach get another plunder chest from the plunder chest. Then there's Donkey Kong, who always goes for the Bowser Bomb.
Ah yes I've seen that happen with Cellular Shoppers too. I think stealing a Plunder Chest with a Plunder Chest is a good move, it prevents the other player from doing the same or potentially stealing good items like Magic Lamps. I think Plunder Chests are significantly less useful in Mario Party 2 though due to the 1 item per player limit, stealing an item randomly if more than one other player has one, and availability. I can see Donkey Kong obtaining a Bowser Bomb even when Baby Bowser is right behind him. Would be great to see.