The actual silicon on the sylicrilic is not loose at the top and bottom per se. You can pop it up with your finger, but in actual usage of the case, I've had absolutely 0 issues with looseness. The sides are more loose than the top and bottom, but yet again, in actual use, I have had no problems.
This is largely due to how tight the plastic part sits on the rubber, and prevents the silicon from going anywhere. Plus the silicon on the silycrilic is a harder silicon than I expected when I was buying the case, and as such it doesn't move in regular use.
Plus the soft touch plastic just feels so good. I was concerned initially, but I promise you that if you pick up a sylicrilic, looseness is not a problem, and it is an excellent alternative to an otterbox in terms of protection, and far better in terms of sleekness. Plus the materials it is made of makes it slide in and out of your pocket with extreme ease.