Flasks are not controlled by CITES. CITES rules do not apply to flasks. According to CITES, flasks are free to move internationally without any CITES documentation whatsoever. Flasks can come out of Laos, or China; it does not matter to CITES because CITES does not regulate or have any authority over sterile flasks.
Also, CITES is not an international ban agreement, as most people think, it's an international control agreement. Wild plants could legally get to China from Laos if both Laos and China are CITES signatory nations. Then, the Chinese importer needs to get a Chinese CITES appendix I import permit from the Chinese authorities and the Laos exporter needs to get a CITES export permit from the Laos authorities. These permits must be applied for and the reasons given for the proposed movement of the CITES appandix I plants. If it's for commercial purposes, the permit applications will likely be rejected. However, if the reason is for scientific study, or propagation, by credible entities, an approval at both ends is more likely. It takes months to get these approvals. I've imported blooming size CITES appendix I plants (Laelia jongheana, Laelia lobata), from Brazil (with the intention to resell - a commercial endeavour), by doing this; getting both a Canadian CITES appendix I import permit and a Brazilian CITES appendix I export permit. In my case, the plants were artificially propagated and nursery grown to maturity...and therefore, they were not in flask of course. The CITES rules allow for these exceptions as long as the authorities of the exporting country are satisfied that the ex-flask CITES appendix I plants were artificially propagated and not wild collected.
However, each individual country can also decide to add on extra restrictions, which CITES has nothing to do with. Some countries don't add more rules, prefering to hold true to the CITES objective of preserving rare plants. One of the ways that CITES tries to do that is by deliberately NOT restricting the movement of in-vitro seedlings because no wild collected plant can be made sterile and put into a flask. Therefore, anything in a sterile flask, must be artificially propagated, which is a good thing to encourage as those seedlings being available in the market place take the collection (for export), pressure off the wild plants, helping more wild plants to remain in the wild.
