Is it safe to use a running martingale when riding cross-country?

The running martingale is a training device used to 'set' the horse's head and aid in the horse bending at the poll and/or keeping him on the bit and not avoiding it. As long as a snaffle bit is used the type of saddle doesn't matter. When used the running martingale make sure to use rein stoppers so the rings on the martingale won't tangle with the bit.