diff --git a/R/check.R b/R/check.R
index f2d2cedf8..3602b3899 100644
--- a/R/check.R
+++ b/R/check.R
@@ -159,7 +159,9 @@ can_document <- function(pkg) {
 #' @rdname check
 #' @param path Path to built package.
 #' @param cran if `TRUE` (the default), check using the same settings as CRAN
-#'   uses.
+#'   uses. Because this is a moving target and is not uniform across all of
+#'   CRAN's machine, this is on a "best effort" basis. It is more complicated
+#'   than simply setting `--as-cran`.
 #' @param remote Sets `_R_CHECK_CRAN_INCOMING_REMOTE_` env var. If `TRUE`,
 #'   performs a number of CRAN incoming checks that require remote access.
 #' @param incoming Sets `_R_CHECK_CRAN_INCOMING_` env var. If `TRUE`, performs a
@@ -188,6 +190,10 @@ check_built <- function(path = NULL, cran = TRUE,
 
   if (cran) {
     args <- c("--as-cran", args)
+    env_vars <- c(
+      "_R_CHECK_PACKAGES_USED_IGNORE_UNUSED_IMPORTS_" = as.character(FALSE),
+      env_vars
+    )
   }
   if (run_dont_test) {
     args <- c("--run-donttest", args)
diff --git a/man/check.Rd b/man/check.Rd
index 1a1a4ac7c..51ec0aca3 100644
--- a/man/check.Rd
+++ b/man/check.Rd
@@ -55,7 +55,9 @@ file. Use \code{TRUE} or \code{FALSE} to override the default.}
 \item{manual}{If \code{FALSE}, don't build and check manual (\code{--no-manual}).}
 
 \item{cran}{if \code{TRUE} (the default), check using the same settings as CRAN
-uses.}
+uses. Because this is a moving target and is not uniform across all of
+CRAN's machine, this is on a "best effort" basis. It is more complicated
+than simply setting \code{--as-cran}.}
 
 \item{remote}{Sets \verb{_R_CHECK_CRAN_INCOMING_REMOTE_} env var. If \code{TRUE},
 performs a number of CRAN incoming checks that require remote access.}