What is actually forced upon children that have been christened? I've been christened... can't say it's had any affect whatsoever?
Not significant, basically.

Kinda different I have been christened and wish I hadn't.
My son is Christened as Catholic. I only agreed to it to appease my Mrs' family because they went mental when they found out we weren't planning on doing it.
I'm not Christian so was kind of opposed to it.
From distant memory and RE lessons in the 60's/70's, the Catholic belief was that an unchristened child who died could never go to heaven, their soul would forever reside in Limbo.
Utter crock in the cold light of day, even if there is a supreme deity or force your entry into an afterlife has far more weighty considerations than a blessing with holy water...
Pretty sure the last pope changed that rule, must have spoken to god on his amazing magic telephone, and smoothed it all over with him.
I don't have kids, but wont have them christened, and they won't go to a religious school, all a load of ****.

No. If our son wants to align himself to a religion later on then he is free to make that choice.
Christening?
Is that the ceremony you perform to save money on private school by sending your kid to a free half decent Catholic school?
Sounds like a good idea but i cant believe all this bureaucracy these days, fill out a bit of paperwork, speak to priest and have him process it, mess about with water. Then it goes into a 10 year delay period until your child is old enough to enter secondary school. Maybe we will eventually skip the church step and just have online christenings with a webcam attached to a supersoaker.
In all seriousness. I went to a Catholic school. It is one of the best in the southeast of England. It never forced religion on anyone and the teachers were as sceptical or more so than the students. Church which we attended twice a year, involved life lessons from our talented comedian priest and were less about faith and more about not being a knob.