You shouldn't have to worry about it. Most of the really dangerous stuff is hard to get to and those that know aren't interested in killing your calc (though it *is* possible).

Besides. If anything *did* become public, you'd know about it. Hit us up on IRC sometime if you want to learn more. It's where all the hax are

EDIT: More information about my concerns have been stated by another member of our wonderful forum. I share much of what he had to say about it, and then some.

Has a calculator every been completely junked? BrandonW bricked a few, but he made a fix for that. The only thing I guess you could really screw up would be the LCD. Unless maybe you replaced 0000 with jp 0000.

well that would suck as one of my ports is already dead (i/o)  well not completely. if you hold the cord in just the right position...

Both TI-Z80 and TI-68k calcs can be killed. But those who know don't behave in an irresponsible manner, and don't tell anybody untrustworthy - they have to find by themselves in the appropriate programs.
Due to obfuscation, no antivirus could be reasonably efficient against viruses, BTW.