The problem with online training videos is that it's hard for the lay person to determine 1) if the quality of instruction is any good, 2) there may be conflicting schools of thought the video doesn't tell you about and 3) little nuances that an in person trainer might catch.
1) True...you can also wind up with a bad coach at a camp but there is a little less randomness there (if you go to a quality camp that you trust you know some vetting has gone on)...and you could also wind up with a bad in person trainer but the feedback you receive from the kid's coach over time (whether things are going better or not) is a check on that.
2) As to conflicting schools of thought...since my background is GK and my son is a GK, for example: how the GK should handle one v one penetrations from the wings....most coaches will tell you to use the traditional method which leaves both post equally guarded but leaves the GK vulnerable to a move to the center such as a rollover which will leave the far post exposed....others will use more experimental techniques (like the crazy Ivan)....unless you've studied yourself a lot of material it's hard to take it at face value.
3) Nuances. Again from GKing...say for example if you are teaching a keeper how to dive...the video may miss some nuances such as holding the ball down to the ground as a 3rd arm, diving forward, diving with a power step, not twisting your arm over, rolling over, or landing on your elbow. Only someone in person can correct that. Once the player or parent has built knowledge, however, videos can be a good resource, such as for example, learning new/rarer moves. But for the basics, they are a poor substitute and you gen. get what you pay for.
You also left out paid videos/DVD such as those from amazon....somewhat more reliable than the online stuff, particularly if put out by a reputable org, but the same issues persist as with free online.
