Definately not unreasonable at all. I have a St Bernard who, although it hadnt occured to me at the time we got her makes me feel so much safer.
I know some people hear St. Bernard and think "oh my God!!!! they'll eat us out of house and home.. etc.." ala Beethoven. She doesnt, she eats her way through 1 large bag of dog nuts per week, hasnt really cost much more than any other dog I've ever owned to feed (including my teeny tiny yorkshire terrier sized mutt), the vet had warned us not to feed her too much. Shes a perfect child friendly dog - apparantly St. Bernards are renowned for this. Very protective of our kids too. I adore her. She does drool a huge amount though and when shes shedding its a nightmare.
Some might say also that St. Bernards have too much of a well known gentle personality to deter a burglar but I couldnt agree less. Her sheer size would deter anyone - a male can be expected to be approx 16 -17 stone fully grown and a female approx 14-15.
I live in the middle of nowhere, like Evenstar, very isolated and rural. My mother does like "next door", which is a field away. She spends approx 6 months a year abroad though. My dh works away at times (a week here and there) and approx 1 -2 nights a week hes away til about 3am.
Anyway, last October, my dh was away for the week about 3 hours away with work and my mother was abroad, I came home from work, had dd with me, heavily pregnant and it was very dark. The sensor light was on up at my mothers house, I got really unnerved for some reason, rushed dd inside and locked the door. All my pets were in with me, so werent setting light off. The sensor light kept going on for about 5 mins and then going off (I was peering from my dark sitting room). My St. Bernard went crazy - shes such a gentle, loveable, sweet soul I didnt think she had it in her, she never behaved like this before - she started to throw her whole body at my patio doors to get out, stood at our door looking up at my mothers bearing her teeth , snarling and growling (never seen this before or since) and barking... the light went off and stayed off. She usually sleeps in our utility but refused point blank to move for me and slept across the bottom of the stairs for the entire night.
I have never heard a bark as loud as hers in my life and know her size and the noise of her would have terrified anyone.
Went into work next day and heard there was apparant robberies in my area (I work for emergency services) within the past week...
She makes me feel so safe. I love her.
Sorry for going on...