I expect that
a) Search engines are quite busy.
b) They will not go though all your pages because there simply are too make pages on the internet to index them all.
c) If they get the meta tags for the first 5 or so pages, they have petty much got an idea of what your site is about, which is enough to make it searchable.
they don't do a word-for-word search of your pages.
(imagine the size of the database for that!)