According to the
APEC BTC website, FAQ #15 :
Question 15 – Can I use the ABTC for non-business purposes, such as tourism?
The ABTC is not designed for tourism purposes, but some economies may facilitate entry for cardholders depending on their circumstances. Please refer to the relevant economy for individual entry arrangements for cardholders and tourist visits.
The
US website takes it a bit further...
Can I use my U.S. APEC Business Travel Card for personal travel, such as vacation?
No. The APEC Business Travel Card is for members who travel frequently on short-term visits within the APEC region to fulfill business commitments. To use the U.S. APEC Business Travel Card, you must be traveling solely for business purposes to the foreign APEC economy.
Realistically for US card holders I'd agree with the comments above - tell the truth and worst case you'll get bumped back to the regular line.
For non-US card holders when visiting countries that would otherwise require a visa for personal travel it could well be a very different story...