I am curious about which of these scenarios would be considered the Runner trashing a card:
The Runner has installed a Parasite onto a piece of ice, and the ice is eventually reduced to 0 strength, resulting in Parasite's effect trashing it.
The Runner ID of choice is Noise ("Whenever you install a virus program, the Corp trashes the top card of R&D"). The Runner plays a virus, causing the top card of R&D to be trashed.
The Runner plays Forged Activation Orders on an ice that the Corp could legally rez, but the Corp player declines to rez it, trashing it instead.
The Runner plays Forged Activation Orders on an ice that the Corp cannot legally rez, thus forcing the Corp to elect to trash it. Normally I do not answer rules questions before a card is released, but I will make an exception for draft cards.
1. The Runner’s card trashed the ice, so Hostile Infrastructure triggers.
2, 3 and 4. The Corp is the one trashing the card, so Hostile Infrastructure does not trigger.