Scope Creep Control

There are times when clients would want you to do more than the project scope as defined in the contract. However, if you are not careful as the project manager, you will end up using up your contingency budget, as well as running into deficit thereby running the project behind schedule and beyond budgets – loses incurred thereupon.
The first thing an effective project manager should do is to ensure he/she knows the scope as well-defined in the contract and engineering documentations. Then he will develop a Change Management platform to engage clients with any change(s) that may erupt, which usually does anyway, duly endorsed by both customer (client/company) and contractor.
That will go a long way to pruning the scope creep; the client too will be careful of what they ask for beyond the contract scope, because the system is in place to control the creep.
I will like your takes on this.
Thank you