It certainly was! I remember connecting to Tymnet and Sprintnet/Telenet as a teenager, probably around 1990 or 91. Someone on a local BBS gave me a username that let me connect to QSD and another European chat system. Someone on there had taken over the "system" account on a VAX and was giving out accounts that let you use it as PAD. This went on for weeks. The company must've freaked when they got their x.25 bill. Zero security in those days. The early Internet was just as bad.