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Legend
And that is on WOTC for setting it up that way. I wouldn't think it would be all that difficult to set permissions such that you only have access to files that were uploaded after your DDi join date.
For articles I could see charging a fee for previous releases which would be close to as if you had a DDi membership all along.
For the Character & Monster Builder youd need to do it differently. There's been good ideas discussed on ENWorld previously (typing from iPhone ATM so search is a PITA), and by actual software engineers not hobbyists like myself. One comparison I liked was with Hero Lab.
However, I tend to agree with the "good will" side of the piracy debate. Yes, intelligently design software, but pirates are always going to be there and they're often going to be one step ahead of corporations. Punitive measure usually end up disenfranchising some existing customers, which may look like acceptable loss on a balance sheet (if its even taken into consoderation) but there's a trickle effect and a critical mass at which that comes back to bite you in the ass. Instead, focus on retaining and steadily increasing that loyal customer base, because the dividends pay off in the long run. Basically, fighting piracy is a losing battle, but a healthy and expanding customer base is always a win - and the two are rarely in opposition.