TTH, if I had a penny for every time I've seen it happen I'd be living comfortably.
Here is only 2 examples from my personal list:
Male 10 year old blue Doberman, owner surrender at MCAS, reasoning: they had a baby and didn't have time for their senior dog
Female GSD, AKC papered(not that it means anything), the family called our rescue finally after having the dog TIED up in their backyard for an entire year. Reasoning: they had a baby and didn't want to deal with their pet anymore. That beautiful dog came to us with many behaviorial problems that could have been easily prevented. 4951