It's a funny little tidbit that inevitably gets tossed around in every championship or conference championship round of team sports that there are always a small number of T-shirts made in advance that depict each of the surviving teams eventually winning the title. The actual winner will have their T-shirts immediately thrown on them in the postgame celebratory chaos and quickly placed on sale to the victorious fans, while the loser's shirts never show their face in American public if the league can help it. They are quietly transported to some part of the world, typically impoverished, where the locals don't care about the sport and don't care what's depicted on the shirts as long as they have clothing to wear. This process is these days not quiet enough for someone to keep from finding where exactly this season's shirts are headed and incorporating it into the requisite trash talk.
That isn't the only piece of merchandise made in advance, though. The actual game tickets are printed in advance as well. It takes some time to get tickets out of the printer and into the hands of fans attending the games, and teams want and need this to be done before the game takes place. But the process can very possibly take longer than the time between when a team qualifies for a particular round of the playoffs and the time that round starts. In order to buy themselves time, tickets are printed and sold early by teams still alive at that point. It's then a simple matter to cancel and refund the tickets if the team doesn't make it, or if the team is not so nice (often they're not), bank the money and offer regular-season tickets for next year instead.
But these tickets don't see much circulation either. They may remain on-continent, but you can't wear a game ticket. And there's no sentimental value; the tickets are sold to fans of the team, fans who are not exactly going to be inclined to hang onto a reminder of a failed season and playoff games that they had hoped to attend but which ultimately invited someone else. The tickets will usually simply be thrown away or returned to the team (or incinerated if the team never sent them out), though perhaps not until someone takes a self-loathing picture of them for mass consumption.
It isn't particularly often that either T-shirt or ticket ends up in enemy hands.
According to this LA Times article from 1986, all teams in Major League Baseball still in contention going into September were required at that time to print off playoff tickets, and when playoff tickets are printed off, it's for the entire playoffs. They have to take that last-minute miracle run to the title into account. This article from the Baltimore Sun on August 22, 2012 suggests that such a policy remains in place. Therefore, it can reasonably be inferred that when, going into September 1, 1990, though no team was officially eliminated yet (though some were getting close), those who were 10 or fewer games back on the division leads, or in the lead, needed to start putting the wheels in motion. In this case, in addition to the leading Red Sox, Athletics, Pirates and Reds (all of which held their leads), that meant the Blue Jays, White Sox, Mets, Expos, Dodgers and Giants also needed to take playoff ticket-printing seriously, just in case. That in turn means ten teams printing World Series tickets when only two sets will be needed- namely, those of the Reds and Athletics.
I don't know what happened to the other sets. But I do know that at least one set of White Sox tickets survived, was framed, and entered public circulation. How do I know this? Because today, I located that set inside Clara's Antiques here in Watertown. And while the tickets may have originally been priced at a combined $150, in the end it only took $12 for them to fall into the hands of a Cubs fan.
We Cubs fans, we know a little something about suffering.