I think the wording of your poll might skew the results.
If anyone I "knew" had a seizure I might think well, I know this poster who wrote about her seizure from Ultram and then put a "yes" for a poll answer. Just a thought.

If you take other medication that lowers the seizure threshold (including alcohol and many SSRIs or related drugs like Wellbutrin-Zyban), have a history of seizures, or exceed the maximum dose, I would avoid tramadol.
Even then there will be some people who have seizures.
But as you wrote, it is rare.