So someone shares the sequence without any context and someone else grabs it and conjectures the context themselves.
What if they share positional information from a known sequence: pi[3000:3040].
What if they share positional information from a known sequence: pi[3000:3040].
OTOH assume knlowedge of nothing but the magnet link list torrent file, if you just downloaded the linked torrent files without to procede to download when in doubt about copyright infringement, that woould not be careless.
Your argument extends to how can any string of data be illegal, putting copyright into question, but that's a different debate.