yes you are right, but I assumed if people see a cloud of condensed fog over their LN2 bath they should remove that by a) filling up the bowl completely e.g. some LN2 drips out of the bowl b) blow the fog away before you dip
I think the original poster meant the relatively low heat conduction of liquid N2, which causes boiling around the crystal immediately after plunging.
The best way to freeze things is to put a small container of liquid ethane or propane into a liquid N2 bowl, and plunge into the ethane/propane (this methods was suggested earlier).
Petr
