Hedging on a pair with equal SL and larger TP is a very common method for news trading. If things go well, it's an easy way to profit. If the spreads get to wide or the market does a wipsaw, it's an easy way to lose some money. If the broker officially forbids news trading, then it's a TOS violation. It's not arbitrage.
Arbitrage (as claimed by Fx brokers) is deliberately trying to send an order when you KNOW that the broker's price is lagging and will give you a better entry than you deserve. This would be virtually impossible if you enter hedged orders at the same time.