When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
If you jumped into a cold truck and fired 'er off without using the glow plugs regularly, you'd likely do some damage eventually, but a one-time occurence isn't a big deal. Once you started the truck, the glow plugs activated, and did what they could to heat the combustion chambers, so your faux pas had minimal impact.
On my truck, the computer code I run in my chip has a certain amount of "glow plug logic" built in, compared to my stock program. When running the stock program, my glow plugs cycle for a full 45 seconds every time I start the truck, regardless of how warm the engine might be. When running the chip program, the glow plugs cycle fully when the engine is cold, but when restarting a warm engine, the glow plugs sense this, and don't cycle at all. At times like that, when restarting a warm engine, I don't wait for the WTS light. I just turn the key, and let 'er rip.