I don't -- not at all.
"Rip off"?!?!?? What a foolish idea.
It doesn't matter who comes up with a good idea for everyone to find it useful. Refusing to implement something that PAYING customers could benefit from out of hubris or pride is just, well, childish and idiotic. This sort of barbarity was, in part, at the heart of the rise of open-source, community based software.
Give appropriate and prominent attribution to those that first thought of it and implemented it. License it if necessary. But don't avoid highly useful features in strong demand because "you didn't invent it". Believe me, there are plenty of people out there without that arrogance that will eat your lunch in competition for customers.