Yes, but we do not have any support to 
transaction save files. I personally have 
a hard time when I need someone reporting 
a bug to upload their savegames (and that 
happens only when the file is already a 
"bad file", anyway).

People could try to get 100% completion 
savegames or have someone hack it; Both 
can be done more smartly by using the 
cheat menu or cheat level editor (it ought 
yo be more documented than savefiles, 
even), and are not something we encourage.

But then we have Murphy Law. If someone 
can do something the right way, OR by the 
wrong way, someone WILL do it the wrong 
way.

I would not call this critical (and my 
initial proposal for a quick patch would 
be a banner  informing to never load a 
savegame from internet).

We also have that updating to fix this 
would change savefiles compatibility, so I 
think unlikely to a proper, real fix being 
deployed for 1.0 or anytime soon. But I'm 
not a coder.