Curiosity: stickers from the manufacturer or from TradeEx?
If the manufacturer I don't blame them. I had a motorcycle a long time ago that had a huge 6" x 12" factory safety sticker on top of the tank (wear helmet, no children, blah, blah, blah...). Asked dealer to remove it: they said they could not by law. Long story short Internet said use a hair dryer, no chemicals because it would ruin the top coat. I had to run the tank dry and heat the sticker to (what felt like to me) a bazillion degrees with a paint stripper, sweating bullets I'd bake off the pain or ignite gasoline/petrol fumes to get it off. I told the dealer about this and the mechanic overheard me. He laughed and said that is why they truly refuse to remove them: they don't want to be liable for a new gas tank paint job.
If it was TradeEx... probably typical anti-sticker removal glue used in most retail stuff. That sh!t is horrid, but normally I see why.