It's not, which I explained further in the post with "How, you ask? Idk, that's for you to figure out. Park your carrier in-system and use its market, or go to a starport in a neighboring system, or... etc., etc."
The Trailblazer ship is not needed to do it. lmfao. Can you even read, bud?
The colonization ships (or any of the construction sites, really) don't have the same interface as any of the other commodities markets, and right now they are the main thing people are delivering their cargo into when they buy from Fleet Carriers. Hence the Trailblazer ships/construction sites are the primary sites where people are getting bitten by the Fleet Carrier cargo bug.
Admittedly, I don't understand your advice, even as a description of an idea. You haven't gone into specifics. Leaving 1 ton of a commodity in your hold at all times will not prevent the "nothing in cargo" error from happening while you are buying commodities from a fleet carrier. You can very much pop into a fleet carrier with 1 ton of cargo, and then buy an additional 100 tons of something, either of the same type or a different type, and your right hand panel will continue to show 1ton, and only 1ton, until such time as you refresh the board. If you leave the carrier in that state, there will be problems when you arrive at a Colonization Ship or Construction Site.
You can refresh the board only by backing out of the commodities market and then opening it up again, or else by quitting to title screen and fully reloading the game. At a construction site, there is one screen and one screen only, so there is nowhere to back out
to and no way to refresh the not-exactly-a-market interface. So you have no option but to quit and reload the game.
If you're suggesting that flying around with 1 ton of otherwise irrelevant cargo in your hold will somehow fix this - it would be easier to take the suggestion seriously if you had tried it for yourself, or were willing to describe in clear language what you think someone should be doing, here.