Hopefully, someone has thought of installing combined GLONASS/GPS receivers...
Unfortunately, it is reasonable to assume there is already and amply supply of weaponized satellites in orbit. So whether you use GPS, GLONASS, Galileo or BDS, the odds are not insignificant that ‘the other guy’ has a plan to make you irrelevant.
The enemy gets a vote, especially when the enemy has been stealing our technology for decades.