Though not in this thread, the modern push for weekly or more frequent Communion is often (as it has been presented in my experience) tied to the idea that since the Lord's Supper is a means of grace, having it more will help the ignorant, scandalous, and less mature be less so. To me that is sacramentalism and misses the point that it is not simply the receiving but also the preparation and post-celebration contemplation that is the means of grace (which is clearly and wonderfully laid out in the LC).
This is quite important - I come from a background where the breaking of bread was essential to the morning worship service every week. Indeed some would have called the service the Breaking of Bread. Yet, and this dawned on me only when I studied and came to appreciate the whole concept of what a means of grace is, and that the LS is a means of grace, that at the same time as emphasizing the importance of the LS in fact making it essentially the be all and end all of the worship service, they denied the very concept of the LS as a means of grace.
Where then did this emphasis on the necessiry of the LS come from? If the supper did not spiriitually sustain and bring grace to the participants why were they so keen to have it and have it so regularly? There can as far as see be only three possible answers: 1) bare obedience out of habit, custom, practice, peer acceptance (i.e. no theological basis) 2) a works ethic that understood the bare act of obedience being itself a way of receiving blessing from Christ or 3) sacramentalism (in spite of theology) where they essentially has an ex opera operato understanding that they would be blessed by the action of communion.
I don't think that's where most reformed advocates of weekly communion are coming from, but I think there is a danger there for the unwitting. In addition the blessing of the sacrament will be tied to some extent to the application we make by faith to it. So merely having it weekly will not necessarily increase benefit if we are not carefully, faithfully participating in it each week.
My position is that given the dire warning issued by Paul about casual participation, and given that there is no clear evidence that weekly communion is required that at the very least sessions/elders should be free to make a prayerful consideration of what frequency is most likely to get the balance of preparation and participation benefit. In my opinion weekly is not optimum, but certainly permitted.
Another thing that borderline annoys me, not in this thread by the way, is that Calvin is often bandied about..."Calvin preferred weekly", yes I understand he did, but he never convinced his fellow ministers or elders! The question, on this and any other point of theology is not "whether Calvin held it or not, but whether Calvin made a strong enough exegetical argument that we should follow him in this. It would appear that the bulk of the Presbyterian and Reformed churches have not believed that he did.