This is probably the worst advice ever for a few reasons:
1. You don't know how to do any of these moves, which can be dangerous and are illegal for white belts under almost every rule set. Heel hooks are considered dangerous by virtually the entire sub grappling community and are usually only trained by very experienced grapplers.
2. You'll learn less if you just try to find tricky ways to beat upper belts. It might work once, but if you get good at passing guard that will work far more often.
3. If you as a white belt go for a heel hook or some other leg lock on an upper belt, they will think (with justification) that you're not safe to train with. If an upper belt thinks you're not safe to train with, they won't teach you anything, and they very well might protect themselves by dominating you and never letting you work anything at all. That would be my response, at least until I felt you'd learned better etiquette.
Just try to stay relaxed and work what you know. Don't be afraid to ask a few questions about how to deal with specific positions. I'm never offended by white belts requesting explanations of how I did something, though I might not tell them if it's something that's way over their head. BJJ takes a long time to learn, establishing a reputation in your gym as a safe, relaxed, but focused student will go a long way towards upper belts helping you improve both formally and informally. You're not going to beat brown and black belts (to the extent that anyone 'beats' anyone in rolling) for years and years, so focus on learning and don't worry if they decide to submit you.