Best Practise - bringing in contextual values from audience?

Hi,

I'm confused as to what's recommended practise talking contextual values working with EMD/RPL compared to Classic Campaign/Built-In Functions (BIF).

When working with BIF you had all columns from the selected audience directly available.

E.g. if you have an audience with RIID_ and COLUMN_A you could in BIF get away with adding the audience to the campaign and anywhere within the campaign write $COLUMN_A$ and get the value.

What's the equivalent working with RPL?

Is that really adding the audience as an independent Data Source and mark RIID_ as a lookup key? That works for the actual launch but what to do then when the recipient clicks 'web version' two days later and the RIID_ with corresponding COLUMN_A is no longer present in the audience? Or is the solution to play around with some Dynamic Variables. I hope somebody can provide me with some input....