Some really good points have been made on this thread!
As a High School coach and parent, I share the following;
Players need to get work during the summer! Quality work! If that means paying to play on a travel team, then so be it. It is sad to say, there are HS coaches that send out the rule "my team or no team" and that is not fair to the player and program. I have had players play on travel teams, show up once in a while for a summer HS game and no questions asked. I am glad they are playing quality baseball. Sure, I would like them to play with our summer squad to keep the core playing together, but I am in agreement, its all about exposure and the players get more exposure at the travel showcases and tournaments.
If your local legion program has quality coaching, a quality schedule and venues to get exposure, that should be highly considered when making the final decision. In short, decision should be pondered by the player and his parents without pressure from the HS coach. Let's face it, a player is not under any obligation to commit to his HS team during the summer. However, most HS programs offer the opportunity and that is what it is, an opprtunity to take or leave.
Long story short, players need to do what is best for them, like finding the right fit with respect to college programs.
As for the "in season" issue, if a player has made a commitment to play HS ball, his commitment is to finish what he started. The HS season ends soon enough and travel baseball picks up where the HS season ends. I know this is going to get some negative feedback, but it is my opinion for whatever its worth. Why would a parent want his son to play 5 or 6 days a week with his HS team, then go play a double header on Sunday? Is there any rest or recovery period, no. Let's not forget the term, "Student Athlete" and schoolwork. 7 days a week for baseball is a little extreme for me as a parent much less a coach. When I took over my current program, I ran into a lot of flack with some dad coaches (JV players) that felt that their kids can and SHOULD do both. Let's look at this for a second, "Johnny" pitches on Sunday for his Dad's team, shows up Monday and Tuesday with a sore or tired arm. "Johnny" is a pitcher and position player and coach has plans to play and/or pitch "Johnny." Is this fair to the HS team? In my opinion, No, a commitment was made to play HS ball and the coaching staff and his fellow players count on "Johnny" to play and help his team. This has happened in many places and I have seen it first hand. If "Johnny" wants to play with his Dad and not the HS team, then that is a decision for the player and his parents. So, option B, find a HS coach that will allow you to do both.... That happens as well.... I have run a travel program and we did not get the HS players together until after the HS season was over. As a parent, I did not let my son play on another team during the HS season, nor did I consider it an option. Life is all about choices, make one and stick with it.
There are great travel programs in Florida and elsewhere throughout the country. If this will help a player get to the next level, and if a family has the financial resources to fund this, its a great option.
My final thought is this, a player needs to do what is best for his development as a player, ensure he will get quality playing time and at bats and if legion or travel baseball options in your area are quality in nature, it becomes a decision of what level of hardship the player and family will go though (i.e. financial, travel etc.).
Again, like college baseball, find your best fit and have fun during the summer, it goes by so quickly.
I apologize in advance if I have offended any Legion or travel coach as this is my opinion on this subject for whatever its worth.