You know what, there’s a small chance they would if they knew. But let’s say the Pentagon stopped all silos and kept it hush. Russia and China would never know whether they stopped or where remaining ones would be.
Under the terms of the New START treaty, the US and Russia conduct inspections of each other’s nuclear weapons programs:
The treaty provides for 18 on-site inspections per year for U.S. and Russian inspection teams
Both countries are intimately familiar the other’s weapons systems.