Bob,
Just a short reply
Here at TRI we have many PCB's with Removable / Temporary 
Solder Mask.

We manufacture many different kinds of auto switches.
 There design dictates a bulb 
assembly after wave solder.  If the landing has solder seepage  the contact will not be reliable and or not able to assemble.
And all of our auto makers would be very upset when the bulb would not work.

Note: These are none soldered contacts to the landing so that the
bulb can be replaced when and if needed.
 This is but one .  I know of many others.
hope this helps.
Nancy

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