diff --git a/reference-implementation/__tests__/parsing-scope-keys.js b/reference-implementation/__tests__/parsing-scope-keys.js
index 6b50c2c..4993f3a 100644
--- a/reference-implementation/__tests__/parsing-scope-keys.js
+++ b/reference-implementation/__tests__/parsing-scope-keys.js
@@ -62,7 +62,7 @@ describe('Relative URL scope keys', () => {
 });
 
 describe('Absolute URL scope keys', () => {
-  it('should only accept absolute URL scope keys with fetch schemes', () => {
+  it('should accept all absolute URL scope keys, with or without fetch schemes', () => {
     expectScopes(
       [
         'about:good',
@@ -87,14 +87,13 @@ describe('Absolute URL scope keys', () => {
         'filesystem:http://example.com/good/',
         'http://good/',
         'https://good/',
-        'ftp://good/'
+        'ftp://good/',
+        'import:bad',
+        'mailto:bad',
+        'javascript:bad',
+        'wss://ba/'
       ],
-      [
-        'Invalid scope "import:bad". Scope URLs must have a fetch scheme.',
-        'Invalid scope "mailto:bad". Scope URLs must have a fetch scheme.',
-        'Invalid scope "javascript:bad". Scope URLs must have a fetch scheme.',
-        'Invalid scope "wss://ba/". Scope URLs must have a fetch scheme.'
-      ]
+      []
     );
   });
 
diff --git a/reference-implementation/lib/parser.js b/reference-implementation/lib/parser.js
index 9e1a9ea..583a520 100644
--- a/reference-implementation/lib/parser.js
+++ b/reference-implementation/lib/parser.js
@@ -1,6 +1,6 @@
 'use strict';
 const assert = require('assert');
-const { tryURLParse, hasFetchScheme, tryURLLikeSpecifierParse } = require('./utils.js');
+const { tryURLParse, tryURLLikeSpecifierParse } = require('./utils.js');
 
 exports.parseFromString = (input, baseURL) => {
   const parsed = JSON.parse(input);
@@ -92,11 +92,6 @@ function sortAndNormalizeScopes(obj, baseURL) {
       continue;
     }
 
-    if (!hasFetchScheme(scopePrefixURL)) {
-      console.warn(`Invalid scope "${scopePrefixURL}". Scope URLs must have a fetch scheme.`);
-      continue;
-    }
-
     const normalizedScopePrefix = scopePrefixURL.href;
     normalized[normalizedScopePrefix] = sortAndNormalizeSpecifierMap(potentialSpecifierMap, baseURL);
   }
diff --git a/reference-implementation/lib/utils.js b/reference-implementation/lib/utils.js
index 1050d84..6f04e5c 100644
--- a/reference-implementation/lib/utils.js
+++ b/reference-implementation/lib/utils.js
@@ -1,9 +1,6 @@
 'use strict';
 const { URL } = require('url');
 
-// https://fetch.spec.whatwg.org/#fetch-scheme
-const FETCH_SCHEMES = new Set(['http', 'https', 'ftp', 'about', 'blob', 'data', 'file', 'filesystem']);
-
 exports.tryURLParse = (string, baseURL) => {
   try {
     return new URL(string, baseURL);
@@ -20,7 +17,3 @@ exports.tryURLLikeSpecifierParse = (specifier, baseURL) => {
   const url = exports.tryURLParse(specifier);
   return url;
 };
-
-exports.hasFetchScheme = url => {
-  return FETCH_SCHEMES.has(url.protocol.slice(0, -1));
-};
diff --git a/spec.bs b/spec.bs
index c973a35..4d47aa8 100644
--- a/spec.bs
+++ b/spec.bs
@@ -332,9 +332,6 @@ To <dfn>register an import map</dfn> given an {{HTMLScriptElement}} |element|:
     1. If |scopePrefixURL| is failure, then:
       1. [=Report a warning to the console=] that the scope prefix URL was not parseable.
       1. [=Continue=].
-    1. If |scopePrefixURL|'s [=url/scheme=] is not a [=fetch scheme=], then:
-      1. [=Report a warning to the console=] that scope prefix URLs must have a fetch scheme.
-      1. [=Continue=].
     1. Let |normalizedScopePrefix| be the [=URL serializer|serialization=] of |scopePrefixURL|.
     1. Set |normalized|[|normalizedScopePrefix|] to the result of [=sorting and normalizing a specifier map=] given |potentialSpecifierMap| and |baseURL|.
   1. Return the result of [=map/sorting=] |normalized|, with an entry |a| being less than an entry |b| if |b|'s [=map/key=] is [=code unit less than=] |a|'s [=map/key=].