The Boston Police Department has indefinitely suspended its use of high-tech scanners that automatically check whether drivers have outstanding parking tickets, lapsed insurance or other violations after a Globe investigation raised serious privacy concerns. The police inadvertently released to the Globe the license plate numbers of more than 68,000 vehicles that had tripped alarms on automated license plate readers over a six-month period. Many of the vehicles were scanned dozens of times in that period alone. The accidental release triggered immediate doubts about whether the police could reliably protect the sensitive data. It also raised questions about whether police were following up on the scans, since numerous vehicles repeatedly triggered alarms for the same offenses.