Step 1: Games WILL PROVIDE NO REMEDY FOR INDIRECT, CONSEQUENTIAL, PUNITIVE OR INCIDENTAL DAMAGES ARISING FROM IT, INCLUDING SUCH FROM NEGLIGENCE, STRICT LIABILITY, OR BREACH OF WARRANTY OR CONTRACT, EVEN AFTER NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.
Doesn't mean someone can't sue 'em anyway. EULA's have been thrown out in courts before.
But, on the general topic, if strobe lights annoy you, turn them off in your server. If you're vulnerable to seizures, then don't play Blockland, or other video games for that sake.