An Anomaly in Ballot Rules

The Government has proposed that a trade union may only call a strike if at least half the workers involved in the dispute vote in a ballot.

Consider two possibilities:

(1) Out of 1000 union members, 501 vote in a ballot and 251 of those voting vote for a strike.

(2) Out of 100 union members only 400 vote in the ballot, and 399 of those voting vote in favour of a strike.

In case (1) 251 people out of 100o vote for a strike, and there would be a strike, but in case (2) the votes of 399 people would not be sufficient to prevail.