Buying based on a warrenty deed followed by a deed of trust.

[Account Closed]

I am doing some title searches for up and coming Pa sheriff sales.  I am only doing current owner searches but have a question.  So I read the following:

When a seller conveys land to you by way of a warranty deed, he certifies or warrants that there are no existing liens against the property.

So is it safe to say that  when I see the transfer of ownership via the warranty deed and at some later date a mortgage/deed of trust, that I can assume all previous liens prior to the mortgage had been satisfied, as well as the mortgagee has free and clear title?

This is assuming the abstract company did there job correctly for the bank, and that the attorney who prepared the warranty deed did their job correctly too.

Am I missing something, baring annoying, easily remedy clouds.