First of all, why would Light want to hide of Misa, within in a group of friends?, what would have been if Misa didn`t identify Light as Kira and she didn`t have any distinctive mark for him to identify her?, another meeting?, wouldn`t it be to suspicious for light to go somewhere else for another meeting? And if she had some distinctive mark, how would he know her name by it?, would he go searching in the streets for her face?
Next thing is the message of Misa after she identified Light, why would she send a tape saying "found you", wouldn`t it be enough if she met Light?
And even sending it a day after the "real meeting", although she faked the date so that it would seem as if they met on the 30th?
Another point is, why would L try to "bait" Misa by promising her a lighter punishment and why would Light fear she would be catched, did they both get stupid?
Last of all why didn`t interfer Rem, when Misa said Light could even kill her when she isn`t useful anymore?(Ok a weak point, since I don`t remember, when Rem got dedicated to Misa, someone knows, when it was in the manga?)