I'm sure if you included a read me in the zip, as well as a breif on who made what, giving the rightful credit out, there shouldn't be a problem. Especially concidering that it isn't payware, and is available elsewhere on the internet (which if you want to get into detail over; is other people hosting space for you to distribute information). I really don't see the issue here.
I think You are missing the point...
The answer is "No!"
. not, "lets discuss it."
People in the locomotion and TTD community respect each others files and creative rights.
By Joe blow distributing BR set files or IA set files , My files, etc. with his maps, you get several issues;
1 You end up with a 125 meg map.
2 You step on other peoples toes.
3 you destroy all quality control
, almost daily (a little longer on other sets) older files are updated with new graphics, stats, bug fixes, locked to other newer files, etc. by distributing older files then what is available in the original set, you ruin how sets are intended to work. By having only one point of distribution, this can not become an issue.
4 as you pointed out, they are available on the Internet. why download the same set more then once? All you need to do is provide links to the downloads.
5 in some certain cases, some older files are somewhat considered abandoned and OK to redistribute as the host is likely to go away. (there not many of these but the earth slopes was one)
6 in some cases, you might wish to change an objects properties for a specific reason, you may contact the author and get permission provided you give credit and a new name to not conflict with existing stuff.
and yes i would report BB... and i have