That's why the sentence ends … to the extent we think it necessary for the Service.

Possibly. Due to the fact that we are dealing with spoken language, even if it is legalese, there will always be some degree of ambiguity and room for interpretation. Here, that ambiguity lies in the phrase "we think is necessary."

Therefore there will always be a tiny chance left for one party to get bitten in the ass down the line. The company has to decide if its them or you that is exposed to that slight risk.

Good luck finding a company that picks them rather than you.

Rereading, I realise that I haven't been entirely clear. I hope you get the idea. IANAL.

"...to the extent we think it necessary for the Service."