No. If you're having problems with assemblies and/or PDBs being locked, the likely culprit is Visual Studio, assuming you have it open at the same time as .NET Reflector. The problem seems like it might be more prevalent with Visual Studio 2005 than Visual Studio 2008.
The PDB files are actually locked by the Visual Studio hosting process for your startup project. The screenshot below illustrates the presence of this process for one of our projects:
The hosting process locks the PDBs when you start debugging. To force it to release its lock on the PDB files you just need to rebuild your solution.
You may also find that disabling the Visual Studio hosting process is helpful, although be aware that if you do this, it will take longer for the debugger to start up. To disable the hosting process, right-click on the startup project in your Visual Studio solution, and click Properties on the context menu. Then go to the Debug tab. It should look something like this:
Now just uncheck Enable the Visual Studio hosting process, save your project, and you're done.