[AccessD] Framework Discussion - set up question

I think the main problem developers have with it is really the problems
users create when they start fiddling around with things they're not
supposed to -- and that's a different basket altogether. If a user doesn't
have access to the tables, they can't build a lookup field and mess stuff
up. If the developer uses a lookup field, then the developer simply needs to
compensate throughout the application, including those queries Charlotte was
talking about. However, I think most developers would skip the lookup field
and compensate. 

Susan H. 

What's impractical about Lookup stuff in a table design?