To my knowledge, if you were a member in the past, then no you can't get the free 14 day trial. Only accounts that have never had members in the past are eligible.
You can get it if you were a member in the past, however you have to have been f2p for quite some time. They will have sent you an email if you are eligible for it. If no email, you aren't eligible.
since p2p players are so much cooler than p2p people (sarcasm)
its a marketing ploy by jagex and a smart one at that, had i known how much more badass p2p is than f2p i would have started playing p2p much earlier. All said its mainly being exploited by people botting on the trial accounts but some tricky trade/buy limits have been implemented to deter this.