[tunap]

The problem, as I see it, is (the Alphabet Agency) has a proven ability and now authorization to do X to Y but promises to never to do it to Z. This is the point where trust comes into the equation. As has been shown via FISA courts, warrantless eavesdropping & sneak/peak ex post facto warrant abuses, trust no longer exists. Sorta like how the US vehemently denied torture until disclosures & evidence mounted so high they couldn't keep up appearances & now hem & haw about how somebody will be held accountable... some day.

tldr: If they have the ability, you can depend on them finding a credible(sic) excuse for using it just that one, initial time. Thus starts the tide of more rationalizations and the ultimate abuses to follow.