That's a good poit about the wax seal breaking prematurely. I can already hear people wanting whole new decks because their seal was broken. I would either need to put a disclaimer telling people that seals aren't guaranteed or use stickers. It would be nice if someone could print authentic looking tax stamps. They would be a nice touch.
A tax stamp is nothing more than a sticker with moisture-activated adhesive. In reality, you could just as easily make stickers that look exactly like tax stamps for deck seals, except the part about them being issued by the IRS or actually charging a tax on them. The deck seal as we know it today evolved from the tax stamp, and was created only because card-buying customers had become accustomed to paying taxes on playing cards for several decades and seeing those decorative seals on the boxes. When the tax was abolished in 1965, manufacturers made their own company seals as a replacement - the Arrco seals in particular looked more like a tax stamp, though with a much less intricate design. (The Bureau of Engraving and Printing has the budget for creating some mighty fine seals, more money than the typical playing card company was willing to shell out.)
Long story short, you can create your own seal that resembles a tax stamp. It'll cost more than using a USPC seal or no seal at all, but it will be a helluva lot cheaper than applying wrappers and wax seals...