Believe it or not, you only get one vote no matter how many rallies you attend. Also, attending a rally isn’t a prerequisite for casting a vote.
“ Also, attending a rally isn’t a prerequisite for casting a vote.”
True, but it gives a general sense of voter enthusiasm. In Trump’s case even people who were never involved in politics were attending his rallies in large numbers. If that were a representative sample of enthusiasm it meant there also a very large number of people who were not at his rallies but very enthusiastic and going to vote.