The backhoe tires needs to be properly inflated when you use the backhoe as it can otherwise allow more rocking when you are digging. You should also use the hydraulic stabilizers, which will stabilize the vehicle when you are using the backhoe for digging.
If the backhoe would actually tilt, it could cause personal injuries and a lot of extra costs. So check the tire pressure in the technical tire manual to ensure that you have the correctly tire pressure based on the load.
For more info regarding the tire pressure for backhoe loaders, visit: www.nokianheavytyres.com