This is the reason that I do not like bagseed. First of all, you really have no idea of 1/2 of the genetics--the pollen could have come from anywhere. Second if it is a bag of something that should be sensi, then it is probably the result of the plant selfing or growing both male and female parts. The problem with this is that plants that arde pollinated are usually not as potent and can yield up to about 75% less than a plant that is not seeded. This is a defect on the gentic level and so the seeds produced are apt to carry this same undesirable trait. If you buy known quality genetics, you are probably going to find others who have grown the same strain. You are going to know the growing traits of the plant, the growing habits, the length of flowering, the nutrient needs, etc, etc. You won't end up with a lanky willowy sativa that needs 9' of headroom and takes 16 weeks to flower. You can choose a plant with characteristics that fit your needs. Do you want an up energetic strain, something in between or something to couch-lock you? Do you need pain relief? What kind of taste and odor do you like? You can probably find it. Limited amount of headroom? There is a strain for you! There are thousands and thousands of different strains with all sorts of growing habits and tastes and smells. It is almost like picking out a fine wine now.
It is absolutely heartbreaking to get 3-1/2 months into a grow and have the plant hermy. There is little you can do without sacrificing yield if a plant grows too tall while in flower or simply outgrows your space. To me, considering that this is a 4 month process and you need hundreds of dollars to set up a proper grow and that seeds are relatively inexpensive and that it takes so much care,energy and love to bring a plant to harvest, spending $50 or 60 on quality genetics just seems to make good sense to me.