In the English Grammar Profile, the negative form of ‘must’ in the category of MODALITY appears at two levels.
Point 21 is A2 and just general form.
Point 149 is B2 and is defined:
USE: RULES
negative forms of ‘must’ to talk about what is not permitted.
*It is not clear what type of usage the A2 level uses. If we look at the 2 EGP examples:
You mustn’t forget to buy …
You must not wear a … (rule!)
We can surmise A2 can use basic subjects and verbs with the structure only. Therefore, B2 should refer to a range of subjects or verbs. For example:
Mr. Iannazzo placed an order at the Robeks and stressed to the staff that the product must not contain peanuts.
However, this overlaps B2 Negation with emphasis.
A search in iWeb for:
must _x _vvi
1 MUST NOT EXCEED 5621 (C1)
2 MUST NOT USE 3904
3 MUST NOT FORGET 3055
4 MUST NOT CONTAIN 2274 B1
collocate search in COCA
1 ANY 12
2 SUBMISSION 7
3 CHARACTERS 7
4 MATERIAL 7
5 THAN 7
5 MUST NOT ALLOW 1747 (c1)
There’s a very strong feeling in the party, mustn’t allow ourselves to be bullied.
6 MUST NOT LET 1395 (B2 phrasal verb object)
7 MUST NOT TAKE 1320
8 MUST NOT MAKE 1173
9 MUST NOT INCLUDE 1035
10 MUST NOT GO 950
11 MUST NOT LOSE 846
12 MUST NOT GIVE 804
13 MUST NOT THINK 719
14 MUST NOT BECOME 685
15 MUST NOT GET 606
16 MUST NOT LEAVE 602
17 MUSTN’T FORGET 570
18 MUST NOT CHANGE 551
19 MUST NOT INTERFERE 531 (B2)
Here’s an example of a sarcastic rule.
Millions of young men are going to die and it mustn’t interfere with the cream of broccoli.
20 MUST NOT ATTEMPT 487
Here’s a TED example:
As we find pathways forward for these individuals,
we must not separate families, we must preserve them.