1. Yes. I’ve seen a dark item of cheap clothing begin to stain in a matter of minutes. The best way to avoid staining is to avoid cheap clothing, get stuff off eBay or watch for Amazon bargains from good brands. If in doubt about any clothing stand your gal on it for a while to see if it stains. Also, if staining does occur and generally fades in time even without any intervention.
2. The cheaper the cost of the clothing item, the higher risk of staining. The dyes will be cheaper than that are used in the fabric which when they get oil from the TPE on them, they bleed back into the TPE. It can stain within 30 minutes if the dye used is cheap enough. It also depends on the tightness of the clothing item. The more squeeze on the TPE, the greater the bleed transfer effect. That’s why you see the greatest stained areas around the hip areas, butt, thighs. and groin areas.