diff --git a/src/script/squirrel_helper.hpp b/src/script/squirrel_helper.hpp
--- a/src/script/squirrel_helper.hpp
+++ b/src/script/squirrel_helper.hpp
@@ -9,6 +9,7 @@
 #include "../core/math_func.hpp"
 #include "../core/smallvec_type.hpp"
 #include "../economy_type.h"
+#include "../string_func.h"
 #include "squirrel_helper_type.hpp"
 
 /**
@@ -79,8 +80,8 @@ namespace SQConvert {
 	template <> inline int Return<int64>       (HSQUIRRELVM vm, int64 res)       { sq_pushinteger(vm, ClampToI32(res)); return 1; }
 	template <> inline int Return<Money>       (HSQUIRRELVM vm, Money res)       { sq_pushinteger(vm, ClampToI32(res)); return 1; }
 	template <> inline int Return<bool>        (HSQUIRRELVM vm, bool res)        { sq_pushbool   (vm, res); return 1; }
-	template <> inline int Return<char *>      (HSQUIRRELVM vm, char *res)       { if (res == NULL) sq_pushnull(vm); else sq_pushstring (vm, OTTD2FS(res), strlen(res)); free(res); return 1; }
-	template <> inline int Return<const char *>(HSQUIRRELVM vm, const char *res) { if (res == NULL) sq_pushnull(vm); else sq_pushstring (vm, OTTD2FS(res), strlen(res)); return 1; }
+	template <> inline int Return<char *>      (HSQUIRRELVM vm, char *res)       { if (res == NULL) sq_pushnull(vm); else {str_validate(res, false, true); sq_pushstring (vm, OTTD2FS(res), strlen(res)); free(res);} return 1; }
+	template <> inline int Return<const char *>(HSQUIRRELVM vm, const char *res) { if (res == NULL) sq_pushnull(vm); else {str_validate((char*)res, false, true); sq_pushstring (vm, OTTD2FS(res), strlen(res));} return 1; }
 	template <> inline int Return<void *>      (HSQUIRRELVM vm, void *res)       { sq_pushuserpointer(vm, res); return 1; }
 
 	/**
diff --git a/src/string.cpp b/src/string.cpp
--- a/src/string.cpp
+++ b/src/string.cpp
@@ -97,7 +97,7 @@ char *CDECL str_fmt(const char *str, ...
 }
 
 
-void str_validate(char *str, bool allow_newlines)
+void str_validate(char *str, bool allow_newlines, bool ignore)
 {
 	char *dst = str;
 	WChar c;
@@ -122,7 +122,7 @@ void str_validate(char *str, bool allow_
 			assert(c != '\r');
 			/* Replace the undesirable character with a question mark */
 			str += len;
-			*dst++ = '?';
+			if (!ignore) *dst++ = '?';
 		}
 	}
 
diff --git a/src/string_func.h b/src/string_func.h
--- a/src/string_func.h
+++ b/src/string_func.h
@@ -95,7 +95,7 @@ char *CDECL str_fmt(const char *str, ...
 
 /** Scans the string for valid characters and if it finds invalid ones,
  * replaces them with a question mark '?' */
-void str_validate(char *str, bool allow_newlines = false);
+void str_validate(char *str, bool allow_newlines = false, bool ignore = false);
 
 /** Scans the string for colour codes and strips them */
 void str_strip_colours(char *str);