Pro tip - less is more:
The "informational sign" should be a Brother P-Touch label saying merely:
Per NH RSA 159:26
Peel, paste, punt.
If anyone ever gets jacked up for carrying in the lobby,
odds are good that the arresting officer
will blindly copy the cite onto the arrest paperwork.
When the defense attorney looks up the cite,
hilarity will ensue.
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Inspiration: perhaps my favorite sign in all of New Hampshire:

[SPOILER="NH RSA 219:7"]NH RSA 219:7
[SPOILER="(In case they move the statute)."]
TITLE XIX
PUBLIC RECREATION
CHAPTER 219
PURCHASING AUTHORITY; EXPENSES
State Reservations and Nursery
Section 219:7
219:7 Repealed by 1983, 422:17, IV, eff. June 24, 1983. –
[/SPOILER]
[/SPOILER]