Yes, most TECs are Power-tolerant (but Power-hungry).
Assuming running at 50% Power to effect a decent delta-T during Summer Imaging, the TEC will draw 1.5A @ 12V for 18W.
If there is a Voltage Drop due to Undersized Wire of 1.5V over 10ft, then to serve that 18W power-level requires 1.7A. This is not bad of an increase in Current, but that additional 0.2A over 4-6hrs of Imaging starts to addup in extra Amp-Hours needed of the Power Source.
If the environment, or the delta-T target, is more severe and the TEC is running near 100%; or the wire is even further undersized at the 28ga commonly sold as "regular" on eBay... Well, then you are looking at running 2.5-3.5A sustained through that wire, and generating enough heat to start melting the PVC Insulation. That is another reason to go with the Higher-Gauge / Higher-Grade Wire such as 18-20ga Silicone-insulated Wire.
After all, you are powering 100's or more likely 1000's $$ of gear; Why mess around saving $5-10 overall on your Wiring??