“adorable” sounds condescending (no need)
“stop them” implies false dichotomy
Counter: Potential positive effects, even if incremental, are desirable, useful, and thus may be sufficient to take such actions (engraving etc.), e.g. a few:
* Awareness / reminder — to anyone who sees it, about the Fourth Amendment’s (4A) existence, and a real example use thereof.
* Appeal to moral duty — chance that a Federal officer may be reminded of their oath to “support and defend the Constitution of the United States against all enemies, foreign and domestic” https://archive.opm.gov/constitution_initiative/oath.asp possibly more importantly than “just following orders”, and possibly take or resist action accordingly (lots of potential positive leeway there, with small discretionary decisions)
* Normalization — the more people see a message openly citing the 4A, the more it seems normal to do so, normal to (at least attempt to) exercise the rights therein.
* Cross-support from other amendment supporters — “4A” may seem similar enough to those who see and recognize and defend “1A” or “2A” or “5A” etc. to also support and possibly propagate the support themselves.
Rejecting something because “That will [or won’t] stop them” is poor reasoning (nearly no battle is won by any particular stop or not), and frankly, a defeatist framing bordering on disuasive propaganda (like the Borg’s “Resistance is futile”)
Much more on why such reasoning is outright wrong from a practical point of view is well summarized by the alternative strategy of Defence in depth: https://en.wikipedia.org/wiki/Defence_in_depth