Does a replacement effect that replaces drawing a card apply when you scry?

Scrying and drawing are two distinct game actions governed by separate rules. Drawing a card is defined in CR 120.1 as taking the top card of your library and putting it into your hand. Scry, defined in CR 701.17, lets you look at the top N cards of your library and arrange or move them — but no cards enter your hand as part of the action.

Replacement effects that modify drawing (such as the one from Notion Thief, which says "If an opponent would draw a card...") only look for the specific event of drawing a card as defined in CR 120.1. Because scrying never produces a draw event, there is nothing for those replacement effects to replace (CR 614.1).

Similarly, effects that trigger "whenever you draw a card" (like Kindred Discovery) do not trigger when you scry, for the same reason: no draw event occurs.

Concrete example: Your opponent controls Notion Thief, which replaces any card draw you would make and gives your opponent a card instead. You cast Opt, which has you scry 1, then draw 1. The scry 1 step is unaffected — you look at the top card normally. Only when you reach the draw 1 step does Notion Thief's replacement effect apply, giving your opponent the card instead.

In short, replacement effects keyed to drawing are completely irrelevant during a scry action because CR 701.17 and CR 120.1 describe two separate, non-overlapping game events.