What kinds of halachot are permissible but we don't tell people?

What kinds of halachot are permissible but we don't tell people?

According to the Tur, you can't sharpen a knife against another knife or against wood, but not against stone. Well, you can sharpen against stone but you shouldn't tell people "ein morin kein".
What kinds of halachot are permissible but we don't tell people?
And for whom is the Tur and Shulchan Aruch intended, if the SA says something, but says not to tell anybody?

Is this like the Rashbam this past week in A"TB"SH?

Who?

alef-tav, beis-shin, etc

I'm still not following.

A"T B"Sh stands for Alef, Tav, Beis-Shin
It's a way of writing in code, alef is switched for tav, beis for shin, and so on.

Is this like the Rashbam this past week in A"TB"SH?

I got that. I'm asking about the Rashbam.

Rashbam (רשב"ם) is a Hebrew acronym for רבי שמואל בן מאיר (Rabbi Shmuel son of Meir) (c.1085 - c.1158). His father was Meir ben Shmuel and his mother was Yocheved, the daughter of Rashi. Like his grandfather Rashi, the Rashbam was a biblical commentator and Talmudist. He was also a leading French Tosafist.

He was the older brother of the Tosafist Rivam and the Tosafist Rabbeinu Tam, also known as Jacob ben Meir. He was a colleague of Rabbi Joseph Kara.

Rashbam was born in France in the vicinity of Troyes. He learned from Rashi and from the Riva. He was the teacher of his brother, Rabbeinu Tam.

His commentary on the Torah is renowned for its stress on the plain meaning (peshat) of the text. This approach often led him to state views that were somewhat controversial (thus resulting in the omission of his commentary on the first chapters of Genesis in many earlier editions of the Pentateuch). Parts of his commentary on the Talmud have been preserved, and they appear on the pages of most of tractate Bava Batra (where no commentary by Rashi is available), as well as the last chapter of tractate Pesachim. Rashbam earned a living by tending livestock and growing grapes, following in his family tradition. Known for his piety, he defended Jewish beliefs in public disputes that had been arranged by church leaders to demonstrate the inferiority of Judaism.

Related Books The Commentary of R. Samuel Ben Meir (Rashbam) on QohelethBy Sara Japhet and Robert B. Salters, The Hebrew University Magnes Press 1985

Very nice.
But I think it's a bit different - the Rashbam is saying that not everything kabbalistic/esoteric is for everyone. That's fine, since we are not all able to fully comprehend esoteric stuff, which is why it's esoteric. But here [in the Tur] we're talking a halachah that should be obscured. Which I suppose is ok if people will likely err with this halachah and will come to sin if they think something is permissible. But that said, for whom is the Tur [and the shulchan aruch] intended? Surely not for simple folk, or at least not for people for whom certain halachot should be obscured, if the Tur is revealing the halachah for all who read it to see.

By the way, with regard to the Rashbam's comments in 3:14-15, note that the Bechor Shore [a younger contemporary of the Rashbam] takes issue with that Atba"sh since by following the logic of the Rashbam, it should be more problematic to pronounce the Name of God that is spelled aleph heih yod heih than it is to pronounce the Tetragammation.

In any event, very nice comment and tie-in to this morning's parshah, existwhere?

Yeah, that's why it's surprising.

...

I wasn't asking who the Rashbam was,rather what did he say in this weeks parshah in regards to what you posted.