Our Toto is totally trained to the wee wee pad but if we are walking her and she has an urge, we also let her go outside. We haven't noticed that it has impaired her inside training at all. The only thing ... if we are on the sidewalk [and we usually are] she doesn't bother to jump over to the grass ... she just goes right there!!
We never disturb her ... just clean up after her!
We are in Colorado and are so thankful that we chose the pad training. Last year we were in Missouri and it was soooo cold. I can certainly sympathize with you!