Yes, I would. It's the same in first aid - you must ask them if they consent to you performing first aid on them or else it's assault.
If they were unconscious that's another matter, but I respect rejections. Honestly, I don't know how society and courts take this, but I'm a full supporter of autonomy. People are can make their own choices (which we should respect, or at least allow), regardless of what we think is good or bad for them.
I'm also of the belief that if you want help, you should ask for it. I don't look highly of people who don't ask for help, then make remarks such as "All he/she did was watch". Likewise, I retort with "All you did was keep your mouth shut".
I believe in positive feedback and vocalising your thoughts. People don't know what you're thinking about - and it's not up to them to guess it. If someone risks "being seen as dumb" and asks for help, they should be rewarded for their actions by having a higher chance of someone helping them. Likewise, if someone wants to keep their pride and act all tough (not asking for help is one of these acts), they deal with the resultant consequence.