Do you refer friends to competitions?

When I say 'refer friends' to competitions; I mean do you tell your friends the website url/link, forward email newsletters, tell them about it when you see them face to face or do you tell effectively strangers via comping forum communities?
After all it's a game of luck so why not share it out and see what fate decides?

Or do you prefer to increase your odd's (less people entering) and sneakily enter alone. Rubbing your hands together cackling away in your secret hide away? (Sorry I got carried away there.)

Would you be more likely to share good competitions with your friends if you had an incentive; like an extra entry into the competition, if the company makes a charity donation on your behalf or a small reward like a voucher code?

I would recommend that you start a little syndicate, where you all enter the same competitions sharing any new prize draws leads as you find them.
Then if any of your syndicate wins, you share the prizes between your group. You might need a contract between you or just good old fashioned honour & trust.

Power in numbers.