In general, no.
In particular, depends.
If you banned your teammate's hoover, when they were last pick and wanted to play a FotM champ, no one should blame you for that.
If you're ADC and are just like "No, Sona is a sh*t champ, I don't want her to Support me, so I'll ban your main and fuck you.", you can rest assured someone will report you. Not just because of the fact you banned the champ they hoovered, but because that's just a shitty attitude overall.
And in all cases, keep in mind: you'll get banned if enough people report you. The punishable stuff is just the stuff that enough people agree to report, it's simple as that. Some things are not considered punishable and if one lone nuthead decide to report you for them, you won't get punished. But if enough people agree something is bad and report you for it, in the end you're gonna get punished.