diff --git a/CMakeLists.txt b/CMakeLists.txt
index f1fbb6e1..4f19e0d8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -129,6 +129,15 @@ if(NOT SECP256K1_EXPERIMENTAL)
   if(SECP256K1_ASM STREQUAL "arm32")
     message(FATAL_ERROR "ARM32 assembly is experimental. Use -DSECP256K1_EXPERIMENTAL=ON to allow.")
   endif()
+  if(SECP256K1_ENABLE_MODULE_FROST)
+    message(FATAL_ERROR "FROST module is experimental. Use -DSECP256K1_EXPERIMENTAL=ON to allow.")
+  endif()
+  if(SECP256K1_ENABLE_MODULE_CHILLDKG)
+    message(FATAL_ERROR "ChillDKG module is experimental. Use -DSECP256K1_EXPERIMENTAL=ON to allow.")
+  endif()
+  if(SECP256K1_ENABLE_MODULE_ICEBERG)
+    message(FATAL_ERROR "Iceberg module is experimental. Use -DSECP256K1_EXPERIMENTAL=ON to allow.")
+  endif()
 endif()
 
 set(SECP256K1_VALGRIND "AUTO" CACHE STRING "Build with extra checks for running inside Valgrind. [default=AUTO]")
diff --git a/doc/iceberg.md b/doc/iceberg.md
index ae7fed54..140fc99b 100644
--- a/doc/iceberg.md
+++ b/doc/iceberg.md
@@ -5,15 +5,15 @@ The following sections contain additional notes on the API of the iceberg
 module (`include/secp256k1_iceberg.h`). A usage example can be found in
 `examples/iceberg.c`, which runs the whole flow and narrates it.
 
-**This module is experimental.** It builds by default here, which is a
-development convenience rather than a statement that it is ready. Iceberg has a
-security proof, by reduction to NestedMuSig2's unforgeability, but it is in an
-anonymous conference submission that is still a working draft, and at the two
-nonces BIP-327 fixes that reduction holds in the algebraic group model rather
-than the plain random oracle model. The proof also assumes a property no library
-can provide (that a session label is used once, group-wide) and the known
-ways to lose a key all live in exactly that assumption. Do not put money behind
-this module.
+**This module is experimental.** It is off by default and on in dev mode, and
+both build systems refuse it outright without `--enable-experimental` or
+`-DSECP256K1_EXPERIMENTAL=ON`. Iceberg has a security proof, by reduction to
+NestedMuSig2's unforgeability, but it is in an anonymous conference submission
+that is still a working draft, and at the two nonces BIP-327 fixes that
+reduction holds in the algebraic group model rather than the plain random
+oracle model. The proof also assumes a property no library can provide (that a
+session label is used once, group-wide) and the known ways to lose a key all
+live in exactly that assumption. Do not put money behind this module.
 
 Iceberg lets a *t*-of-*n* group act as a single MuSig2 participant. From outside,
 the result is an ordinary BIP-340 signature: nothing in it records that a group