diff --git a/ci/travis/script.sh b/ci/travis/script.sh
index d4ca77714..d893de372 100755
--- a/ci/travis/script.sh
+++ b/ci/travis/script.sh
@@ -10,8 +10,15 @@
 
 header 'Running script.sh...'
 
-if any_casks_modified; then
-  modified_casks=($(modified_cask_files))
+modified_ruby_files=($(git diff --name-only --diff-filter=AM "${TRAVIS_COMMIT_RANGE}" -- *.rb))
+
+for file in "${modified_ruby_files[@]}"; do
+  [[ "${file}" == 'Casks/'* ]] && modified_casks+=("${file}") || casks_wrong_dir+=("${file}")
+done
+
+if [[ ${#casks_wrong_dir[@]} -gt 0 ]]; then
+  odie "Casks added outside Casks directory: ${casks_wrong_dir[*]}"
+elif [[ ${#modified_casks[@]} -gt 0 ]]; then
   run brew cask _audit_modified_casks "${TRAVIS_COMMIT_RANGE}"
   run brew cask style "${modified_casks[@]}"
 else