Advice Illustrated

Letter 1 is from a person whose sister is dating a registered sex offender. Sister says he's innocent, but research shows he's not, or at least that he's not being truthful with sister. LW doesn't want BF around, to protect the kiddies. Sister says this ain't fair. Prudie says better safe than sorry, and make sure sister knows she's been sold a line.
I say that although I'm opposed to sex offender hysteria, here it seems clear that there's a choice between children really being harmed, or hurting your sister's feelings. Guess who wins?
And yet... he says he plead guilty to protect his family. And research shows that he plead guilty after his sister made a suicide attempt. Which may or may not have meant he was guilty. I could imagine her trying to commit suicide because she realized she made a false accusation and didn't know how to get out of it. And if so, he could consider even a good lawyer bad if the lawyer let him plead guilty despite being innocent.

Video letter is from a person who attends musicals with a friend. Friend sings or hums during the musical numbers. Prudie says he should tell her to shut up.
So do I. Duh. But I wouldn't be threatening elbows. I'd try a more Judith Martinian tack: "Darling, I know you must not realize your singing along. I find myself doing that sometimes, the music is so delightful. Please give me a nudge if you ever find me doing it; I know you'd want me to do the same for you."

Letter 2 is from a woman who gave her MIL a nice but inexpensive Xmas gift. MIL gave LW an expensive gift, and has now called LW a cheapskate and a dolt (for not knowing that MIL is allergic to cheap or something). MIL even wants LW to return her gift! Prudie goes into the "if this behavior is odd, MIL might be senile" shtick.
I say what Smag says. Return the gift, and have no further contact with this individual. She is dead to you (and as she has decided not to be your mother-in-law, she has no connection with any children you may have now or in future). And again, WHERE IS THE HUSBAND????? And no, Prudie, he doesn't think this behavior is out of the ordinary for her, he's just "confused". He's confused because he's a pussy who doesn't know what to do, which is to grow a pair and deal with the bitch rather than leaving his wife to ask advice from some online advice lady.

Letter 3 is from a person whose coworked got fired because he can't deal with people. She thinks he's Asperger's. Should she tell him? Prudie says yes.
I say, if you care about him and his situation, of course you should. Maybe you're the one with Asperger's?

Letter 4 is from a person who have been (probably fairly) accused of cheating at high-stakes poker. What should LW do? Prudie says LW needs to tell friend that friend is no longer going to be playing because he's been accused of cheating.
I agree with Prudie, and with her wonderment that LW wants to be friends with someone he thinks has stolen from him.