Yes, for most of the online contests, number of submissions contribute to "penalty". More wrong submissions give you lower place despite solving the same number of problems and same time for solves.
But for some of the OI contests (eg IOI), it is fully based on scores only and completely ignoring the number of wrong submissions.
I know that codeforces style (AKA ICPC style) has this penalty system, but if you are given the choice, which would you choose?