Yet this opens up as if there isn;t an existing trade system. Moreover and imho, more importantly, there's no fooling aspect. Unless! Again like val (stop judging, i only been to one beautiful res event DX)! You can choose to fool them and send them the fool squishy instead. Is it too much copycat of val? That was really fun in any case. All the advertising for accepts/declines (what would be fools/true trades) became completely objective and it was hilarious to hear people make their ads within "context".

Oh maybe! The squishies are not claimable until after the event but during it, said squishies, tricks and trades, etc happen over some makeshift stock market of some kind. Because stock market is ripe 'n ready swindler base!
Trading event squishies (or other item maybe but i am bias yunno) : when you fufill a trade, it's a result of either fooled or traded. "fooled" being if you complete the trade with the incorrect request. Both agree on the trade itself but like a game of cards neither knows until the trade is complete from both ends, whether it was done in earnest. So both could "fool" or both could "trade" or neither. Edit:There could be prizes or forum badges for "white lies" (if ya get my drift) or no "april sq" altogether, simply "fooled" with duplicates you don't need. Requiring you to go forth and fool somebody else. I do recall that there was 30min time limit on past event - was it to keep from overloading the server. That was perhaps everybody's greatest frustration. Other than warping in people for their milstones that is ;)

So in comparison to val, the systems could be similar to: incoming/outgoing ---> fooled/traded, accepts/declines --> april/fool squishies and or items. Pretty complete of an idea, Just dunno if it might not brew presence of passive aggressiveness amongst people. Which is hopefully, where in/outcoming come in. Since in val, we advanced or had to advance into both to gather the prizes of both, we also have to fool/trade equally to attain the items, prize  milestones of fool/trade, there can be  prizes like those of the wings and tatoos. Themed, rare or otherwise prizes.
Not to mention gather the full set of items to be traded somehow. May the trickiest person win? Yes, i loved val's event. Thank you again and i pray for squishies always.

Edit - after secrets reply: The feature of pets able to get sick kicking off with all pets getting fleas.