When you first used the Android Market, you are presented with Android Market's Term of Service. One of the clauses is this:
2.4 From time to time, Google may discover
a Product on the Market that
violates the Android Market Developer
Distribution Agreement or other legal
agreements, laws, regulations or
policies. You agree that in such an
instance Google retains the right to
remotely remove those applications
from your Device at its sole
discretion and without notice to you.
So, if you want to block Google from using their remote uninstall, you cannot use Android Market. However, note that their Term of Service only allows them to uninstall applications that "violates the Android Market Developer Distribution Agreement", this implies that Google can only uninstall applications that are installed from Market (since an application that was not distributed from the Market never accepted to be bound by the AMDDA, and therefore cannot "violate" the AMDDA). If you sideload your application, Google cannot touch your application.
If your company want to use Android Market but you don't want to allow Google to use their remote uninstall on your company's devices, I suggest you contact Google to make a special TOS agreement.