Nice necro bump as I haven't seen this particular video. The person doing the video is correct in that the trigger springs were weak. JG sells updated springs that are cheap and work really well. If the Timney is installed properly and with a stronger trigger return spring, it is absolutely safe to carry as it uses the same firing pin safety, dingus, and drop shelf as would any other Glock based trigger. How much of a G force would be required to make the sear drop? I'm not an engineer but I would think the drop would have to be massive for the sear to drop and one that would never occur while carrying it. Even if it did drop, the firing pin safety would catch the firing pin as long as the VE is not depressing the firing pin safety. Not an issue if you want to carry with a Timney installed but there is a much better option now.
The GPT is that better option and removes all doubt about safety in a SA Glock trigger. It is better in every regard except it comes with a polymer shoe vs the Timney's aluminum one. The Timney has a pre-travel screw in the housing but the pretravel screw can loosen over time and then you can have an unsafe condition where the dingus will not engage. Point is, go with a GPT and install pre and post travel screws in the housing along with a minus connector and some other massaging and you will have the nicest Glock trigger out there and one that will rival just about any trigger on the market for any gun.