For your reason, no.  It's your cel, do as you 
wish!  Why should that be of concern to anyone 
else?????

BUT.....

If you bought the cel just to resell it in the 
first place, I'd have to say it isn't 
as "ethical".  

Again, it's your cel, your choice... but the 
latter has the potential to upset people 
(especially those who would have gladly bought 
the cel at the price you paid for it, only to 
have it resold at a higher price.)

JMO.  ^^;

jINx