Yeah, even if juice jacking were impossible, you're still likely to get really crappy power that shortens your favorite device's lifespan. Cables without data pins (and I do have a few) don't solve that. My preferred solution is to plug a compact charger into an AC outlet. Alternatively, charge a $50 battery and then charge your $500 phone from that. Bring two if you want zero downtime. You'll still want something that's decent quality either way, but those aren't hard to find at reasonable prices.