Does Google cap query returns?

Image representing Google as depicted in Crunc...

Image via CrunchBase

When I look at Google “webmaster” returns for this site I note that for more or less every weekday for the last fortnight it reports my site was returned as an answer to a search query exactly 1300 times, the week before that it was 1000 and the week before that 900.

So, am I to assume that Google caps the number of times that a site can appear in a search query?

I suppose I can see some justification for that as a way of stopping people spamming the index – but it also seems quite a crude tool. What if, for instance, some issue I write about a lot (Linux paging?) becomes a hot property and I have already used up my 1300 quota?