I think you can trust VC firms because they are incentivised to not steal your idea. In fact, they see that many ideas there will probably be 4-5 entrepreneurs pitching them the same idea potentially with the same/slightly different spin on it.

By incentivised, I mean that if a VC firm is known to steal ideas then entrepreneurs, will generally avoid them (especially if the VC firm that stole the idea was an early-staged VC) which means that their deal flow will dry up – something no VC firm wants.

Having an EIR and/or HIR allows a VC firm to provide their portfolio companies with a better level of service. VC firms are providing more than just money, they’re providing help with resources which are/maybe too early for a startup to have and when you do need them they’re helping you fill those roles – specifically they’re providing things like finance, marketing, HR, PR help etc and having an EIR and/or HIR increases the amount of service they have offer to their portfolio companies.