Truthfully, I've never really felt it discriminated personally but I have seen it around. It's not just the Philippines as I've noticed all sorts of countries have. If I were to point out the worst, I'd probably say Hong Kong.
And when I say that I've not really felt discriminated, it's a bit of a feat since I usually under-dress. When I say under-dress, think sandos and tsinelas.. with the uber-comfy sweatpants. Somehow, this became a discussion topic in the past and it was summed up because on how I interact - the walk, talk, etc. is "different" (don't worry, I try to keep my self-ego-boosting to a minimum

)
I've seen discrimination with my mom though while we were shopping at SM since talagang pangbahay usually suot niya. Yun tipong 5-year+ clothing plus a Secosana bag... until somebody sees her paying for everything with her BDO rewards card

ahh.. the wonders of accumulating more points than you can spend. A TrueValue cashier once peeked at her remaining point balance tapos nahuli since she uttered an expletive out loud.. that was like a 5 minute long sermon from a very-pissed-off-mom afterwards.