Dave

I would question whether those soft bump caps are legal for use.

From the AMA Pylon Racing Rules:

4.2.1. Every person going onto the racecourse or between the designated sideline and the racecourse (see racecourse diagram), and all officials, whether on or off the course, shall properly wear a helmet approved by OSHA, DOT, ANSI, SNELL, NOCSAE or other recognized organization that certifies safety equipment.

From the link on the softbump caps you posted:

This bump cap is NOT a safety helmet and does NOT meet OSHA or ANSI requirements for head protection.

DO NOT USE as a sport safety helmet. DO NOT USE when ANSI compliant head protection is required or needed.