No JREs or JDKs installed
1. Install JDK 7 b137
(http://j2se.east.sun.com/arc/ds_build/1.7.0/nightly/2011-03-31/windows-i586/jdk-7-ea-bin-b137-windows-i586-31_mar_2011.exe)
include public JRE and JavaDB
2. Uninstall JavaDB 10.6.2.1
3. Uninstall JDK 7
4. Try to uninstall JRE 7
I probably launched IE 7 after clicking uninstall.

Expected:
Not to see an option to {uninstall) later

Actual:
I didn't see the Windows Installer files in use Cancel-Retry-Ignore dialog.
I saw our Files in Use dialog offering to install later.
I cancelled and did't select later.

5. Closed IE
6. Try to uninstall JRE 7

Expected:
It would uninstall.

Actual:
Fails to remove silently.
Log contains
Action ended 16:35:43: CheckFIUCancel. Return value 2.
and
MSI (s) (60:84) [16:35:43:426]: Product: Java(TM) 7 -- Removal failed.
MSI (s) (60:84) [16:35:43:436]: Windows Installer removed the product. Product Name: Java(TM) 7. Product Version: 7.0.0. Product Language: 1033. Removal success or error status: 1602.
I am Ok deferring this, it is not readily happening and while it needs investigation it does not appear to be a frequent case.