Skills hording

in driving and programming skills is it legal to horde or have more than 2 balls at a time?

From the appendix to the Game Manual that deals with the Skills Challenges:

There is NO mention of having more than 2 balls in the Skills Challenge rules.

According to the skills manual, it states

So we can use the interpretations of the game manual to also aid us in figuring out what is/isn’t legal in skills.

According to the rules, it’s impossible to hoard balls or caps. So if we are talking about the original, default-defined non-VEX word of “hoarding” then yes it is legal. In fact, you can hoard while in possession of game elements as well:

The only thing that is NOT legal is having possession of more than 2 balls: