It can actually be both. A scalp is an arbitrage. An arbitrage is buying of a product for immediate gains. Could be a game, could be a stock, could be toilet paper.
In the truest sence it is generally a SIMULTANEOUS profit, but for gambling purposes anything that offers profit either before or after the fact I consider a scalp (arbitrage).
But to me (not to get anal with lander) a hedge is only an insurance bet that doesn't offer a profit. So if you have Det to win a series at +200, and they are tied 1-1 going into the final game and they are Yanks are -220 in that game and you want to buy off Det a little, then that in my mind would be a hedge. BUT if Yamks were only -180, then that would be a scalp. Because you can make a profit both ways. A hedging scalp might be more correct. But it is the same as taking leads, you bet early and buy back late, same difference.
But in direct answer to your question, yes I do do it. Especially when I am in Vegas. Leroy's is the only book in town that does it. But sometimes their lines are WAY out of whack. I also generally bet them after I getthe numbers for the first two games, that way I can correlate it out to see what I need for odds in the last game. Or you can also simply look at the average odds prices for the pitchers in certain situations to get a bench mark number. So that gives you a lot of possibilities, and a window to work with. If the odds are out of that window then you bet it, if they aren't then you pass. Because to hedge/scalp off you still need to go 1-1. But if they are close and you actually like a team, then you can take a shot too, because then if they go 2-0 you don't need the right number in the first place, and even if they aren't a true sclap you at least have a team you liked in the first place so you aren't stuck with something you don't have some confidence in.
Series bets can be very lucrative, and they are the only bets I make in the NBA now.
But in bases the limits are so small scalping/hedging isn't a way to get a lot of return, you just have more oppurtunitties. But also a larger margin for error. But they are always good to keep an eye out for.
Since I only use two foriegn books I am limited. Pin will offer them from time to time, but with smallish limts, and only on a limited number of series. Plus if they take any kind of action on them they take them right down. So it unless you have a book that offers them all the time the oppurtunities are limited for sure.