I've said it before but "Stop 'n Go" plugs are rubbish. I have the kit and, per the video, they end up falling into the tyre.
Sticky strings are the best roadside repair but few use them properly (and nor does the chap in the video): They should be fully inserted into the tyre and there should be very little excess to cut off. Used like that they form a large mushroom inside the tyre and pretty much weld themselves in.
Yes shop repairs are best but I've had punctures in new tyres, used sticky strings and run them until the tyre wore out.