Installing add-ons on multiple computers

Since I've not been involved in flight simming for a number of years I was not aware of the problems publishers were having with stolen copies of their products.I am retired but travel frequently between Florida and the midwest. Those trips last up to a month at a time. It would be convenient for me to be able to run my regular installation of MSFS2004 on my desktop while at home and a similar installation on my laptop while away.Over this past weekend I purchased several quality (defined as those recommended by many here at AVSIM) aircraft add-ons. Upon inquiry, I was informed by the rep from one publisher that because of theft problems their policy was not to allow the installation of their product on more than one computer. Considering my own situation I decided not to purchase what has been described on this forum as an excellent product.Two other publishers from whom I purchased this weekend, upon specific inquiry in which I outlined my desires, gave their written permission to install their product on both my desktop and my laptop... both of which I own and when one is running I don't run the other. Just have no need to do so.What are the pros and cons about this subject? Many software publishers allow their product to be installed in a similar manner as I have described with the proviso that they not be used as two "copies" running at the same time., i.e., if one has need of both running at the same time one should be willing to purchase the required number of copies.Thoughts on this?