Is providing a slow response to journal reviews a common/good strategy for minimizing the number of review requests? It is well known that in mathematics the process of reviewing submitted papers is quite long. There are good reasons for that; intrinsically, reviewing a math paper involves checking and understanding thouroughly the proposed proof, which typically requires a significant time investment. Also, a lot of academics are always very busy and reviewing may not be the most urgent thing they have to do, so it tends to be pushed back.

But it seems that there are other, maybe not so commendable reasons. Apparently, the common wisdom around me is that you should be careful not to turn in your reviews too soon, or you will be flooded with requests by editors (who are all too happy to find someone gullible enough to hurry doing their reviews) and reviews will take up all your time. This is an advice I've often heard given to young researchers, including by people who can honestly not be accused of neglecting the community service aspects of their work. A lot of people I have talked to have a policy of never doing the review before the deadline or the k-th reminder from the editor. I even heard of a person who would do the review almost immediately after accepting it (when time allowed), but only send it after the deadline or later.

In an imperfect world where doing your task sooner than anyone else will mark you as candidate for exploitation, I understand the need for such strategies. But I wanted to check: 


Is the risk so big? 
Is this practice really generalized (also in other fields than mathematics)? 
Do you have alternative strategies to avoid having too many review requests (of course, one can always refuse reviews, but since it can be delicate to do so too often, one may try and avoid requests themselves)?
I can imagine someone purposefully delaying reviews, but in my experience it's not a widespread or standard part of mathematical practice, and I haven't heard it offered as common advice.  I don't think referees have an obligation to inconvenience themselves to finish a review as quickly as they can, but it seems bizarre to deliberately delay when it would have been convenient to complete the review earlier (or, worse yet, when it was already done but not yet sent).

I don't see a real risk here, or a need to avoid review requests.  There's nothing wrong with turning them down, and you can use a vague excuse like that you are already busy with other refereeing and don't want to cause unnecessary delays for this submission.  In fact, a prompt reply will be appreciated; it already puts you ahead of the people who require reminders to reply to referee requests.  (When a referee declines quickly, there's almost no cost, while it's annoying if I send several e-mails over a period of weeks but never hear back.)  From my perspective as an editor, I'm not looking for people who will complete a review as quickly as possible.  Instead, my ideal referee is someone who is responsive and reliable, who promptly lets me know what they can reasonably do and then does it within the timeframe they estimated.  If they do that, they can turn down as many requests as they like.