What the FAQ commits to
Two statements carry the reassurance. On spend, the FAQ says the change "will not directly result in increased spend for you." On budgets, it says "your daily and monthly budget limits will always be respected." Neither is hedged.
The commitment that matters more sits alongside them, phrased as a limitation: Google "won't automatically adjust your daily budgets or your campaign bid targets." Whatever a campaign is set to on 17 August is what it will be held to.
Google's worked example shows the shape of it. A campaign carrying a Target CPA of $10 whose recent performance has been $5 will begin delivering closer to $10 from that date if nothing is changed. Spend does not rise, because the budget cap is unchanged. What changes is what the budget buys.
Who is in scope
The change applies to Target CPA, Target ROAS, and Target CPC in Demand Gen only, on Search, Shopping, Performance Max, Demand Gen and Travel campaigns showing a "Limited by budget" status.
Outside scope: campaigns that are not budget-constrained, Smart Bidding Exploration, manual CPC, and Target Impression Share. A campaign with budget headroom already bids toward its target, which is the behavior being extended rather than introduced.
Google's recommended sequence is to review the limited-by-budget campaigns running target-based strategies, reset targets to match recent performance where those results are the ones worth keeping, pair the target with a budget buffer that reflects the efficiency being asked for, and then allow one to two conversion cycles before reading anything into the outcome.
What to do about it
Sort by status, then by gap
The affected set is narrow enough to list. Filter for "Limited by budget", keep the campaigns on tCPA, tROAS, or Demand Gen tCPC, and for each one compare the target against what it has been returning over the last month. Campaigns where those two numbers already agree need nothing. The work is entirely in the ones that have been beating their target, because that gap is what closes.
A target left alone is still a decision
Nothing gets adjusted on your behalf, which means declining to act is a choice to accept the target as written. For a campaign that has been overdelivering, the honest question is whether the target was ever set deliberately or inherited from a launch six months ago that nobody revisited.