I believe there is a phrase that goes “All’s fair in love and war”. The thing about this is that fights that involve “cheap” tactics are usually pretty boring to watch. I would not like to watch a high level match won through projectile spamming, its pretty dull.
However, the fighting games of today are more balanced than they were before. MvC3 may have tiers, but each character has the ability (given the right team) to win. This is unlike MvC2 which did not really favor diversity very much. Hell, the best example I could give would be BlazBlue. Every character in the game has the potential to win, given time and practice. Some noobs might delcare some things “cheap” like Tager’s grab, Jin’s “Ice Car”, and Lambda’s swords to name a few. The thing is though none of these are cheap in any way. Tager’s grabs do high damage because he was literally ZERO mobility, Jin’s ice cars can easily be punished on block, and Lambda’s main zoning tool are her swords because rush downs can tear her up if they get in. In this case its a matter of being unable to adapt to the situation. The thought that got me through this was that “its not cheap, I just have not found a way to beat it yet.”
In the end I believe most scrubs are the ones who don’t adapt to the fight. They will continue to try the same tactic (like jumping in SFIV) even though they get punished for it by anti airs. A tactic is only cheap if there is literally no way around it, not because you can’t get around it.