Absolutely.
I have certainly been talked over in non-cooperative overlapping situations, and it can be very irritating. I have also been outright ignored--my favorite was when my spouse and I went to the assessor to question our home assessment--and the assessor only shook my husband's hand and talked to him.
You're right that it just takes a little noticing to realize what kind of situation/conversation you're in. I love my best friend and I love my husband--but I need to show them my love in very different ways. For my friend it involves jumping all over her sentences (and vice versa); for my husband it needs to involve more pauses.
Great point about gently pointing it out and giving people a chance to adjust. I like that a lot.
Thanks for reading and thanks for commenting. Another thing I like about comments and writing--hard for me to rudely jump into your written comment until you've completed it! :)