In maria-5.3-exists2in , using tables and fields that do not exist does not cause an error:

CREATE TABLE t1 (f1 integer);
CREATE TABLE t2 (f2 integer);

SELECT * FROM t1 WHERE EXISTS (SELECT NO_SUCH_TABLE.NO_SUCH_FIELD FROM t2);
does not return an error

explain:

id select_type table type possible_keys key key_len ref rows filtered Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
2 SUBQUERY t2 system NULL NULL NULL NULL 0 0.00 const row not found
Warnings:
Note 1003 select NULL AS `f1` from `test`.`t1` where 0

bzr version-info:

bzr version-info
revision-id: <email address hidden>
date: 2011-10-31 13:44:24 +0200
build-date: 2011-11-01 10:58:26 +0200
revno: 3256
branch-nick: maria-5.3-exists2in