Finding your baby unresponsive and cool to the touch is one thing, finding her blue and cold is another. Yes, babies do sometimes get into deep sleeps and forget to breathe for a long time, then take a deep breath and start again.
According to the paediatrician we saw, under these circumstances they wouldn't expect to find the baby had turned, or begun to turn blue and they were as sure as they could be that that wasn't what happened with dd.
As I said, I don't consider myself to be a paranoid parent. We were given the monitor as a present when we were expecting our first child and kept it and used it right through all three, with it also being used for our nephew in the interim. We used it because we had it, rather than because we were paranoid they would stop breathing.
If we had had repeated false alarms or found it annoying we would have stopped using it, especially as the boys were both good sleepers and I would have been really annoyed if the darn thing had kept waking them up.
In the 7 years prior to dd being born, neither we nor my sister had a similar experience to what happened with dd. The monitor is designed to wait a discrete period of time before going off to take into count episodes of deep sleep. I assume my two boys and my nephew all slept deeply and had hiatuses (sp?) in their breathing on occasion, but the alarm never sounded in these cases - because they weren't in danger.
For me, after the episode with dd, the monitors were just added reassurance - I didn't sleep much for months afterwards anyway, so probably/possibly would have been alerted to a problem anyway.
Dd was in a bedside crib for which we had a bespoke mattress made so that it abutted straight up to our own mattress right next to me from when she was born until she was 12 months old anyway. Despite the fact that she was essentially lying right next to me, when she stopped breathing, neither I nor dh were aware of a problem until the alarm went off. The consultant at the hospital actually said to us that in his opinion the alarm saved her life.
At the end of the day, it come down to personal preference and parenting style. As long as they are not used as alternative to vigilance and conscious parenting, whose business is it whether or not you use one anyway?
I really don't get why people are getting so worked up about it. If you want one and intend to use it wisely rather than as a alternative to being vigilant, surely that's your choice and not something you should have to feel judged for.