Use cars can also do a good job and using pc speakers can do a good job too. Parked car near or besides hawker center facing shops... this shd work given such a short time campaign notice and period.
After this is over, crowdfund sue Election Department for intimidating and harrass voters... they don't give voters enough time to absorb the contents and narratives of the candidates views and to make informed decisions, do due diligence and exercise their options available...