Is this her way of saying she knows we know but doesn't care?

My DH step mom is cheating on his dad.. his dad is a truck driver and gone 6 weeks at a time.. her best friend told us everything and said she has been doing it for over 10 yrs.. Including who all her bfs are.. well apparently she meets guys offline all the time which she does but she has one bf who she was dating before she met my father in law.. who is from around here and she see's him about 3 times a week.. well his work is basically our neighbor.. I can look out my window and watch her pick him up and drop him off all the time.. we have it on camera like 50 times.. literally.. a few weeks ago she caught my DH hiding in a bush video taping her dropping him off.. he tried to play it off but it was more the obvious what he was doing and I'm sure she knew as well.. so yesterday was my sons first birthday and she got him one present.. (she plays favorites with the grandkids and as you can imagine mine isn't the favorite so she treats him differently which is a entire different story and question! LOL) and the present was a tonka truck that talks and its name is Chuck the talking dump truck.. Chuck is her boyfriend! How would you take this if it was you? I take it as she knows we know and doesn't care.. she was there on his lunch break today driving my DH dads car! It's so wrong I hate her she is a rude favorite playing mean hateful woman and she will get hers some day! I hope anyways.. but yeah what do you think that she meant by coincidence? I don't think so!