MIL will forward terrible emails to us but, in public, she will always be the perfect lady.
She will never insult anyone directly but we will learn her true feelings.
At the place where she lives, you can enter a breakfast order at the counter. The order will be delivered to your table. When ours came, MIL thanked the woman kindly and asked about her children. As soon as the woman was out of earshot we got MIL's true opinion. 'She was very slow delivering our breakfast. She also has three children and no husband. That is the problem with these people. They are lazy and never think about their futures'.
FIL enjoyed buying ski jackets. He would buy five or six classy examples a year, wear them once and then give them away to family members. After FIL's death, MIL became a sort of Den Mother to Chinese graduate students at the local University. They became the recipients of FIL's largesse.
MIL doesn't do this any more and there are still a good half dozen jackets in the closet. We suggested that the local coat drive would be happy to have them. MIL would not hear of this because she doesn't want the coats to go 'to the wrong people'.
The problem is that MIL doesn't seem to be dead set against any skin color, religion or ethnicity. She just rolls with whatever drops into her mailbox.
That's why everybody's a little vigilant where MIL is concerned.