They only couldn't sense it, because Sidious was blocking them.
That only goes to show that precognition isn't perfect. I'm sure there are ways to circumvent the ability even without being a monster like Sidious.
Mandalorian could lay a trap, probably with explosives. Attack from a distance greater than the jedi was able to "sense". Using projectile instead of blaster weapons, or even a sonic weapon. I'm sure a mandalorian could come up with plenty of ways i wont.